Fix rascal-core using outdated fields & fix source path calculation for compiler mode

[DavyLandman]

A few fixes for issues found in PathConfig & Rascal compiler while integrating into VS Code.

In the process I've had to rewrite the function, as it was getting to complex to follow.

Note it does not yet implement the design in #2171 but it would be quite simple to do based on this PR (and in some places I already left comments)

[codecov]

Codecov Report

Attention: Patch coverage is 36.00000% with 80 lines in your changes missing coverage. Please review.

Project coverage is 46%. Comparing base (e04a9a7) to head (b58f606).
Report is 14 commits behind head on main.

Files with missing lines	Patch %	Lines
src/org/rascalmpl/library/util/PathConfig.java	32%	71 Missing and 9 partials ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##              main   #2169   +/-   ##
=======================================
- Coverage       46%     46%   -1%     
+ Complexity    6074    6069    -5     
=======================================
  Files          741     741           
  Lines        62224   62258   +34     
  Branches      9300    9302    +2     
=======================================
- Hits         29183   29168   -15     
- Misses       30862   30925   +63     
+ Partials      2179    2165   -14     

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[jurgenvinju]

This looks good to me. Especially the additions to make compiler mode work were still missing and now they are here. Thanks @DavyLandman

Is PathConfig.listModuleEntries still used anywhere? Perhaps we can clean that up.

[jurgenvinju]

I'm a bit unsure about the Rascal-lsp special cases. Have we tested those already?

[DavyLandman]

@jurgenvinju and @sungshik I've rewritten the fromSourceProjectRascalManifest function, since the logic was getting too complex.

It now has 3 sub-functions:

1. rascal setup
2. rascal-lsp setup
3. All other projects

This has greatly reduced the complexity of the code I think.