lint(track_config): add more checks of exercise concepts

[ee7]

With this commit, configlet lint now checks that a track-level
config.json file follows the below rules:

• The exercises.concept[].concepts values must not be in any other
  concept exercise's concepts property
• The exercises.concept[].concepts values must match the
  concepts.slug property of one of the concepts
• The exercises.concept[].prerequisites values must match the
  concepts.slug property of one of the concepts

These rules currently apply to user-facing Concept Exercises only, which
are those with status of active or beta.

Refs: #386

---

Ping @iHiD - would you like another fast release for this one? Please sanity-check the below diff.

At the time of writing (2021-09-05T18:14:00Z), this PR produces the below diff to the output of configlet lint, per track:

go

https://github.com/exercism/go/blob/a167c7853aed/config.json

+The Concept Exercise `chessboard` has `range-iteration` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `elons-toys` has `pointers` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `zero-zilch-nada` has `types` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+

java

https://github.com/exercism/java/blob/30ff7755c73e/config.json

+The Concept Exercise `bird-watcher` has `foreach-loops` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `bird-watcher` has `for-loops` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `football-match-reports` has `switch-statement` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `football-match-reports` has `variables` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `football-match-reports` has `methods` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+

rust

https://github.com/exercism/rust/blob/60147eb56efd/config.json

+The Concept Exercise `low-power-embedded-game` has `tuples` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `short-fibonacci` has `vec-macro` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `rpn-calculator` has `vec-stack` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `csv-builder` has `string-vs-str` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `magazine-cutout` has `hashmaps` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `magazine-cutout` has `intro-types` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `health-statistics` has `string-use` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `short-fibonacci` has `numbers` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `rpn-calculator` has `numbers` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `rpn-calculator` has `match-basics` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `rpn-calculator` has `mutability` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `rpn-calculator` has `loops` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `csv-builder` has `string` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+

swift

https://github.com/exercism/swift/blob/e476a4a070dd/config.json

+The Concept Exercise `bomb-defuser` has `shorthand-arguments` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `bomb-defuser` has `closures` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `bomb-defuser` has `trailing-closures` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `bomb-defuser` has `capturing` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `high-score-board` has `dictionaries` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `master-mixologist` has `while-loops` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `master-mixologist` has `control-transfer` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `master-mixologist` has `repeat-while` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `master-mixologist` has `loops` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `master-mixologist` has `for-loops` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `secret-agent` has `escaping-functions` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `vehicle-purchase` has `ternary-operator` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `windowing-system` has `value-and-reference-types` in its `concepts`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+
+The Concept Exercise `bomb-defuser` has `loops` in its `prerequisites`, which is not a `slug` in the top-level `concepts` array:
+./config.json
+

[iHiD]

Yes please!