Refactoring: Introduce a FSM for OSM file parsing

[lukasalexanderweber]

Through #2907 I remembered a thing I noticed during the implementation of via way turn restrictions, namely the complexity and coupling of WaySegmentParser and OSMReader. Having a short glance on the code today I thought it might be worth bringing up my idea on a refactoring. However I only want to start implementing this if you're interested.

From #2673:

All that being said, I'm not strictly against changing anything about WaySegmentParser and OSMReader and there absolutely is room for improvement. Especially OSMReader is still a somewhat inflexible huge monolith of many different things. The builder in WaySegmentParser is also not ideal, which is something I wanted to fix before, but either forgot about it or ran into some problem, I can have a look again. So feel free to open a PR for your refactorings that we can discuss. Shall we do this first? I can try to re-arrange the code in the way that I think would be appropriate for the new turn restriction handling in the meantime.

I created the refactoring branch but never did a PR since we were too busy with the TR.

The idea is build around a FSM represented by a state-transition table implemented in OSMParser

With this Parser we can parse an OSM file as often as we want, and can specify what exactly should be done with a Way, Relation etc. - If no handler for a specific element is specified it just skips those.

This gives us a nice mental model on the steps we do to create the graph:

Parse1 get Header info and preprocess Ways and Relations

    OSMParser parse1 = new OSMParser()
                    .setFileheaderHandler(new FileHeaderHandler())
                    .setWayHandler(getWayPreprocessor())
                    .setRelationHandler(getRelationPreprocessor());
    parse1.readOSM(osmFile, workerThreads);

Parse2 process Nodes, Ways and Relations

    OSMParser parse2 = new OSMParser()
                    .setNodeHandler(getNodeHandler())
                    .setWayHandler(getWayHandler())
                    .setRelationHandler(getRelationHandler());
    parse2.readOSM(osmFile, workerThreads);

of course there is room for improvement but I thought it would be sad if my thought are lost without discussing them again :)