Fix for multiple build targets at cabal-add

[VenInf]

Fix for multiple build targets at cabal-add

In my current merged solution, cabal-add CodeAction is provided only for the main target.
This was only a temporary solution due to limitations of the getBuildTargets function.
For more information, consult this thread.

Now it was fixed, and you can choose to what target add the dependency.
Video with an example:

cabal-add-continuation-cut.mp4

Also, I changed the title for the CodeAction, to a hopefully better one.

Implementation details

I changed the functions getBuildTargets and buildTargetComponentName to
the getBuildTargetComponentNames that handles GenericPackageDescription and gives ComponentNames of all targets.

What isn't implemented

• Previous tests were built assuming that there is need to wait only for one CodeAction. Now this leads to a race condition.