Add actions to control the build tool throug hls

I'm especially looking at the Visual Studio Code extension ghcide and comparing it to the intero based "older" Haskelly extension.

What I like with the Haskelly extension is its appeal for casual Haskell users or beginners. Haskelly has some smart detection of the project type, and then places proper action buttons in the status bar area that's reserved for that use, like you see in this screenshot


The casual user or beginner often looks for that kind of experience: having a visual editor and simple buttons to build, test and run.

Would be great if you can "borrow" that logic from https://github.com/haskelly-dev/Haskelly