ENH: allow extraction of coins ends in COINS.stroke_attribute

[martinfleis]

Adding the option to pull out the information about the ends of stroke groups.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 98.2%. Comparing base (4037c70) to head (dd351ec).
Report is 88 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##            main    #646     +/-   ##
=======================================
+ Coverage   97.4%   98.2%   +0.8%     
=======================================
  Files         26      38     +12     
  Lines       4328    6254   +1926     
=======================================
+ Hits        4214    6139   +1925     
- Misses       114     115      +1     

Files with missing lines	Coverage Δ
momepy/coins.py	99.0% <100.0%> (+3.7%)	⬆️
momepy/tests/test_coins.py	100.0% <100.0%> (ø)