Implemented capabilities API on VFS

[DavyLandman]

This API adds a capability feature to the remote VFS feature that was added in #2641

It allows servers to communicate that some parts of the VFS are not or partially supported.

[rodinaarssen]

Nice work, this is a very valuable addition to the remote resolver registries.

Looks good overall, just some remarks here and there

[codecov]

Codecov Report

❌ Patch coverage is 0% with 114 lines in your changes missing coverage. Please review.
✅ Project coverage is 46%. Comparing base (c912f8b) to head (a3b816f).
⚠️ Report is 2 commits behind head on main.

Files with missing lines	Patch %	Lines
...mpl/uri/remote/RemoteExternalResolverRegistry.java	0%	41 Missing ⚠️
...c/org/rascalmpl/uri/remote/jsonrpc/Capability.java	0%	21 Missing ⚠️
...almpl/uri/remote/jsonrpc/CapabilitiesResponse.java	0%	20 Missing ⚠️
src/org/rascalmpl/uri/URIResolverRegistry.java	0%	8 Missing and 4 partials ⚠️
.../rascalmpl/uri/remote/jsonrpc/CapabilityLevel.java	0%	12 Missing ⚠️
...rascalmpl/uri/remote/RascalFileSystemServices.java	0%	5 Missing ⚠️
src/org/rascalmpl/uri/watch/WatchRegistry.java	0%	3 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff            @@
##              main   #2792    +/-   ##
========================================
- Coverage       46%     46%    -1%     
+ Complexity    6720    6719     -1     
========================================
  Files          829     832     +3     
  Lines        66583   66689   +106     
  Branches      9955    9975    +20     
========================================
- Hits         30778   30773     -5     
- Misses       33420   33531   +111     
  Partials      2385    2385            

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[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud