Change ProjectedPathConversion to use continuation passing style

o Simplifies PathValueBuilder
o Pulls out projectionStepConverter
o Removes ProjectionSteps
o More tests
Merge pull request #2291 from davidegrohmann/ronja-named-path

Change ProjectedPathConversion to use continuation passing style
Moved named path handling to ast rewriting by inlining them as PathExpressions

o Removes named path from QueryGraph
o All named path patterns are turned into anonymous patterns after inlining
o We only inline named patterns in MATCH for now (as opposed to MERGE, CREATE, etc.)