Allow envFile alternative to env in java.test.config

[nerdkid93]

The VS Code launch.json file allows specifying envFile in addition to env. However, there does not appear to be a similar mechanism when running tests via this extension. It would be super handy to be able to have 1 file specify the env rather than duplicate it in both .env and .vscode/settings.json.

[jdneo]

The next release will happen around the end of Nov.

[jdneo]

End game verification steps:

1. Add an .env file in project
2. Add envFile in java.test.config
3. Write a test case to verify the .env file is picked:

assertEquals("value", System.getenv("key"));