Refactor NearbyStopsFinder to follow strategy pattern

[habrahamsson-skanetrafiken]

Summary

This PR is a pure refactor and shouldn't change any behaviour.

The NearbyStopsFinder has three different behaviours depending on two different parameters:

• Default street search, used if the graph has a street network.
• Straight line search, used if the graph doesn't have a street network.
• A special search considering TripPatterns that is used in conjunction with one of the above. Used if the ConsiderPatternsForDirectTransfers feature is enabled.

The different branches makes the code difficult to understand and difficult to test. This PR refactors this code to use the strategy pattern by extracting a common interface and having one class for each behaviour.

This work is in preparation of some work I need to do on access/egress search as part of #5848.

Unit tests

Unfortunately there is no tests for this piece of code. I would like to add some in a follow-up PR.

Documentation

I added and updated javadoc.

Bumping the serialization version id

Nope

[codecov]

Codecov Report

Attention: Patch coverage is 92.00000% with 4 lines in your changes missing coverage. Please review.

Project coverage is 69.45%. Comparing base (b9e54d2) to head (960480d).
Report is 25 commits behind head on dev-2.x.

Files	Patch %	Lines
.../graph_builder/module/DirectTransferGenerator.java	81.81%	1 Missing and 1 partial ⚠️
...earbystops/PatternConsideringNearbyStopFinder.java	92.59%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@              Coverage Diff              @@
##             dev-2.x    #5906      +/-   ##
=============================================
- Coverage      69.45%   69.45%   -0.01%     
- Complexity     17064    17072       +8     
=============================================
  Files           1927     1931       +4     
  Lines          73578    73587       +9     
  Branches        7549     7550       +1     
=============================================
+ Hits           51106    51109       +3     
- Misses         19847    19853       +6     
  Partials        2625     2625              

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[leonardehrenfried]

This is a good refactoring. I look forward to the tests.

[t2gran]

Just one JavaDoc need to be updated.