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.)
Merge pull request #2292 from davidegrohmann/ronja-named-path

Moved named path handling to ast rewriting by inlining them as PathExpre...