Phase out requirement for .no-sublime-package

[FichteFoll]

As discussed in wbond/package_control_channel#7612, it would be nice if this file wasn't needed. This issue is to track progress and alternatives. Feel free to ask me or Thomas, if you're running into a wall or are curious about things.

[rchl]

@daveleroy Do you think it would be fine to store adapters in "Package Storage" (as coined by LSP) and the sublime package schema in User/Debugger.sublime-package?

Not sure if there are any other things that would need to be changed.

[daveleroy]

There probably needs to be some more changes here than just switching where things are stored.

There is no auto update of adapters and storing them inside the package means they get removed when things get updated so users have to get the latest versions after an update.

Things like breakpoints and watch variables also get stored inside the package. The schema for these would need to either remain backwards compatible or have some sort of version information tied to them so they could be invalidated