Make e2e test runner re-usable

[PEZ]

• The e2e test launcher now takes args:
  • calva-vsix: <vsix>, if omitted the development Calva will be used
  • test-workspace: `
• The CI pipeline now tests two workspaces
  • ./src/extension-test/e2e-test (where the test-runner also lives)
  • ./test-data/projects/e2e-sub-projects intended to run some tests with jack-in and clojure-lsp and what not where sub-projects are involved

I don't think this with several projects will scale all that well, but could come in handy for some special project structure. Maybe Polylith is worth it's own e2e testing.

• Fixes Make the e2e test runner re-usable #2057

What has changed?

I have:

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• Made sure I have changed the PR base branch, so that it is not published. (Sorry for the nagging.)
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• [ ] Figured if anything about the fix warrants tests on Mac/Linux/Windows/Remote/Whatever, and either tested it there if so, or mentioned it in the PR.
• [ ] Added to or updated docs in this branch, if appropriate
• Tests
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Ping @PEZ, @bpringe, @corasaurus-hex, @Cyrik