LSP analyze all files in project

[christianparpart]

Analyzes all files within a opened project. That includes those that are not opened. This is the default option (as it seems to match what other LSPs do) but can be explicitly turned off using custom settings object that can be passed during initialization.

[Marenz]

Is this PR still relevant or was it superceeded?

[christianparpart]

Is this PR still relevant or was it superceeded?

@Marenz relevant. and soon ready :)

[cameel]

This is the last thing missing for approval: https://github.com/ethereum/solidity/pull/13150#discussion_r951688759, i.e. I think it won't handle symlinks. But that should be easy to fix. The other stuff are just simple tweaks and the new tests seem good enough for now.