Smoke tests in nodejs

[DonJayamanne]

For #6511

• Only runs smoke tests using the UI Tests
• There are more UI Tests, but not enabled
  • Other UI Tests will be enabled in a separate PR
  • Those other UI tests will be run as part of a separate nightly uitest pipeline (again separate PR)
  • Leaving that code in this PR, no point in removing all of that.

If required I could break the PR into separate PRs as follows:

• Azure Pipeline changes for UI Tests
• Extension code changes to exclude UI Tests stuff (.vscodeignore, .gitignore, etc changes)
• Smoke (UI Test) code changes (only code)
• Smoke (UI Test) BDD feature files
• Smoke enabled (tie all stuff together)

Azure Pipelines

• Smoke (UI) Tests run as a separate stage (in parallel with the standard test stage).
• Build/compile phase of UI Tests run as a separate stage (in parallel with standard build stage)
• In Reports stage, I've added a UI_Test_Report job that will merge all UI Test reports into one (just so we can look at a single report).
• All UI test results are published into Azure Tests reports tab (so we can see results there too - just used an npm package for this).

[codecov-io]

Codecov Report

Merging #7456 into master will not change coverage.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master    #7456   +/-   ##
=======================================
  Coverage   58.67%   58.67%           
=======================================
  Files         493      493           
  Lines       21990    21990           
  Branches     3531     3531           
=======================================
  Hits        12902    12902           
  Misses       8281     8281           
  Partials      807      807

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update 615ea01...e22b973. Read the comment docs.

[DonJayamanne]

@rchiodo @karrtikr @IanMatthewHuff

Ready for review, no rush

[rchiodo]