refactor: Move Bazel wrapper commands into separate file

[vogelsgesang]

This in preparation of adding a new "Measure Coverage" command, but I don't want to make the main extension.ts file even longer. Hence, I first move all the commands which simply wrap underlying Bazel commands into a separate file.

[cameron-martin]

How come some of the commands are still in extension.ts?

[vogelsgesang]

My underlying thinking was:

The commands which I moved out into an own file are direct Bazel wrapper commands.
The refreshBazelBuildTargets and copyTargetToClipboard are not wrappers around Bazel commands, but are UI-specific commands.

I obviously failed to communicate this, both in the commit message, the file name and the function name.

I see two options:

Option 1:

• rename the file commands.ts to bazel_wrapper_commands.ts
• rename the function activateCommands -> activateBazelWrapperCommands
• update the commit message accordingly

Option 2:

• also move copyTargetToClipboard and refreshBazelBuildTargets over

I slightly tend to option 1, because I think we should structure the code based on "features" (wrapping the Bazel commands; providing a tree view; providing code lenses; ...) and not "implementation vehicle" (commands, treeviews, ...). Do you agree with that?

[cameron-martin]

Makes sense - I agree that organising the code around features is better, so I'm happy with option 1.

[vogelsgesang]

I finally updated this Pull Request 🎉 (took me longer than I hoped for. Too many other things going on...)