Selective reference resolving part1

[MDoerner]

This PR introduces selective resolving of references (by module). More precisely, only references of modules referencing a module that gets parsed are resolved.

To achieve this, I had to pull the store the unresolved declarations outside of the DeclarationFinder; they now live on the ModuleStates in a new collection separate from the real declarations. This has the added benefit that the DeclaratioFinder seen by the inspections now really see the undeclared declarations in the DeclarationFinder.

Moreover, I had to change the clean up of references to only remove references from modules whose references get resolved again.

After the changes, the reparsing time in my test project dropped from 25s to 17s when there are no changes of the code at all and to 9s if there are minor changes.

This is only part 1 and not the full story because there are still some open points.

1. The compilation passes, namely the TypeHierarchyPass and the TypeAnnotationPass still run on all modules. (They do not add duplicates, by design.)

2. We do not clean up properly the declarations in the modules that do not get reparsed, namely the supertypes and subtypes added in the TypeHierarchyPass do not get cleaned up. (If an implemented interface gets reparsed, e.g. because the line spacing changed, the existing supertype declaration will be out of date after the reparse. )

[retailcoder]

nice, this will make UseMeaningfulNames inspection fire results for undeclared variables! 👍

[retailcoder]

the reparsing time in my test project dropped from 25s to 17s when there are no changes of the code at all and to 9s if there are minor changes.

That's rather interesting..