check for adt remote filesystem

[marcellourbani]

@larshp I finally found the time to fix this.
Single file rules are mostly working now. Notes:

• some changes are adt specific. Perhaps I should use !== file rather than === "adt" but it's by far the most common case
• the glob stuff is not ideal, but unless we call an extension specific API is the best we can do
• the file search stuff is not strictly related but should work. Was converting / to //
• tasks and run configurations are unrelated but I hate working without a debugger, or restarting the whole thing on every change. With this reloading the window is enough
• there are several type errors, mostly due to version misalignment with core. I fixed a few (not entirely sure about a couple) and ignored others for getting a debuggable build
• all tests pass, formatting.ts is definitely broken anyway

[marcellourbani]

weird, I had to revert my last commit to make tests pass here...

[larshp]

thanks