Extract separate conditions for "equals", "greater than", "absent" during OSM tag mapping, add Portland tag mapping

[leonardehrenfried]

Summary

This is a port of the IBI walk comfort rules that they added to their 1.x fork. Since #4328 already added the walk safety as a parameter during building and routing, this only adds additional conditions so you can have more complex expressions like

• absent
• greater

It would be trivial to add more of these.

Lastly, I also added the tag mapping for the city of Portland (the birthplace of OTP!), which is the first user of these new features.

Issue

#3516

Implements part of #3724

Closes #2751 as it implements the Portland mapper in OTP2.

Unit tests

Lots added.

Documentation

Manually and automatically updated.

cc @demory

[codecov-commenter]

Codecov Report

❌ Patch coverage is 91.80328% with 10 lines in your changes missing coverage. Please review.
✅ Project coverage is 60.73%. Comparing base (eb8cf1b) to head (10ed4a9).
⚠️ Report is 14515 commits behind head on dev-2.x.

Files with missing lines	Patch %	Lines
.../graph_builder/module/osm/specifier/Condition.java	84.90%	7 Missing and 1 partial ⚠️
...ilder/module/osm/specifier/BestMatchSpecifier.java	96.55%	0 Missing and 1 partial ⚠️
...ph_builder/module/osm/tagmapping/OsmTagMapper.java	66.66%	1 Missing ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             dev-2.x    #4593      +/-   ##
=============================================
+ Coverage      60.70%   60.73%   +0.02%     
- Complexity     12240    12255      +15     
=============================================
  Files           1579     1586       +7     
  Lines          63414    63529     +115     
  Branches        6990     6992       +2     
=============================================
+ Hits           38498    38583      +85     
- Misses         22740    22772      +32     
+ Partials        2176     2174       -2     

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[demory]

General comment: would it make sense to include a LessThan condition alongside GreaterThan even though it is not immediately needed by TriMet? Then we would have all of the conditions needed for basic numerical comparison (less, greater, equal, and the ability to combine multiple)