Add baseUri to DocumentFilter

Created by: felixfbecker

This is a proper fix for both #8602 (closed) and broken codeintel for root files (Slack thread). Codeintel extensions need to be able to scope providers to workspace roots. Doing so in pattern does not work, because minimatch is not built for working with URIs (in particular it broke for files in the root).

Considering all options, I decided to go with this solution. Alternatives considered:

• Making pattern work for URIs
  • This is ambiguous with percent-encoding
• Adding explicit filters for repository and revision
  • This is more cumbersome for lsp-client, which wants to scope to the root URI
  • Not clearly defined in editors with file:/// URIs
• A uriPattern property
  • More complex, no direct use case