Allow to run single test / pass arguments to test framework

[dos65]

Based on this question: scalameta/metals#2972

Test frameworks accept arguments that are usually used for filtering tests.
For example:

• ScalaTest: -t "test description"
• Munit: --tests=$REGEXP

It would be nice to provide a way for passing these arguments from Metals.

It might be implemented as a command that shows an input box or a quickpick with previous runs arguments.

Search terms:
#tests

[tgodzik]

I think we might need to change the BSP implementation a bit to allow this. But later we could also provide code lenses for single test cases. Might not be that complicated.

[LaurenceWarne]

But later we could also provide code lenses for single test cases. Might not be that complicated.

I've been playing around with exposing individual tests using lenses based on some of the test discovery stuff:

Nowhere near as cool as the vscode test discovery 😅, but on the other hand it doesn't really need anything special on the client if they already support dap.