Add tests for project detection

[TrevCraw]

• [x] detect project with src/main/liberty/config/server.xml file only (ie. no LMP or LGP defined in build file)
• [x] detect project with LMP config in build file only (ie. no server.xml in project)
• [x] detect project with LGP config in build file only (ie. no server.xml in project)
  • [x] buildscript + apply plugin method
  • [x] plugins block method (both methods of defining the LGP can be found here: https://github.com/OpenLiberty/ci.gradle#adding-the-plugin-to-the-build-script)

Example tests in LT IntelliJ: https://github.com/OpenLiberty/liberty-tools-intellij/blob/main/src/test/java/io/openliberty/tools/intellij/it/SingleModNLTRestProjectTestCommon.java#L110-L214

[aparnamichael]

Added test cases to detect project with src/main/liberty/config/server.xml file only (ie. no LMP or LGP defined in build file) PR - https://github.com/OpenLiberty/liberty-tools-vscode/pull/284

[aparnamichael]

This PR has to update with the latest changes. Also waiting to merge https://github.com/OpenLiberty/liberty-tools-vscode/pull/328.

After that re-review is required.