Address Flakiness in ClearlyDefined API

[robert-cronin]

Description of the PR

This PR attempts to address the recent flakiness observed in the ClearlyDefined API.
Fixes #2273
Fixes #2290

The main change is the addition of a Mock ClearlyDefined API that lets you provide coordinate -> definitions mapping directly.

Stress test results:

❯ stress go test -timeout 30s -race github.com/guacsec/guac/pkg/certifier/clearlydefined

5s: 55 runs so far, 0 failures, 8 active
10s: 112 runs so far, 0 failures, 8 active
15s: 171 runs so far, 0 failures, 8 active
20s: 228 runs so far, 0 failures, 8 active
25s: 286 runs so far, 0 failures, 8 active
30s: 344 runs so far, 0 failures, 8 active
35s: 400 runs so far, 0 failures, 8 active
40s: 459 runs so far, 0 failures, 8 active
45s: 515 runs so far, 0 failures, 8 active
50s: 573 runs so far, 0 failures, 8 active
55s: 633 runs so far, 0 failures, 8 active
1m0s: 690 runs so far, 0 failures, 8 active
1m5s: 747 runs so far, 0 failures, 8 active
1m10s: 805 runs so far, 0 failures, 8 active
1m15s: 862 runs so far, 0 failures, 8 active
1m20s: 920 runs so far, 0 failures, 8 active
1m25s: 976 runs so far, 0 failures, 8 active
1m30s: 1036 runs so far, 0 failures, 8 active
1m35s: 1093 runs so far, 0 failures, 8 active
1m40s: 1151 runs so far, 0 failures, 8 active
1m45s: 1208 runs so far, 0 failures, 8 active
1m50s: 1265 runs so far, 0 failures, 8 active
1m55s: 1324 runs so far, 0 failures, 8 active
2m0s: 1381 runs so far, 0 failures, 8 active

PR Checklist

• All commits have a Developer Certificate of Origin (DCO) -- they are generated using -s flag to git commit.
• All new changes are covered by tests
• If GraphQL schema is changed, make generate has been run
• If GraphQL schema is changed, GraphQL client updates/additions have been made
• If OpenAPI spec is changed, make generate has been run
• If ent schema is changed, make generate has been run
• If collectsub protobuf has been changed, make proto has been run
• All CI checks are passing (tests and formatting)
• All dependent PRs have already been merged

[robert-cronin]

This does turn the test from a proper integration test into more of a unit test of the parsing pipeline, however I think it's okay since we still have the e2e testing to interface directly with api.clearlydefined.io. Open to any counter points or suggestions.

[pxp928]

This is great! This is also related to issue #2290, would you be able to change https://github.com/guacsec/guac/blob/main/pkg/ingestor/parser/common/scanner/scanner_test.go#L343 to use the mock? This can be done in a a separate PR.

[lumjjb]

❤️ ❤️ ❤️