feat(lanelet2_extension): add bus_stop_area implementation

[soblin]

Description

define bus_stop_area in format_v2 namespace

https://github.com/orgs/autowarefoundation/discussions/5097

Related links

#21

Tests performed

Notes for reviewers

Interface changes

add a new map primitive under format_version2 namespace

Effects on system behavior

none

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[codecov]

Codecov Report

Attention: Patch coverage is 58.13953% with 18 lines in your changes missing coverage. Please review.

Project coverage is 16.48%. Comparing base (1d3219a) to head (be7f49a).
Report is 1 commits behind head on main.

Files	Patch %	Lines
autoware_lanelet2_extension/lib/bus_stop_area.cpp	48.38%	13 Missing and 3 partials ⚠️
...t2_extension/test/src/test_regulatory_elements.cpp	80.00%	0 Missing and 2 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #22      +/-   ##
==========================================
+ Coverage   15.84%   16.48%   +0.64%     
==========================================
  Files          40       42       +2     
  Lines        2765     2808      +43     
  Branches     1348     1371      +23     
==========================================
+ Hits          438      463      +25     
- Misses       2239     2252      +13     
- Partials       88       93       +5     

Flag	Coverage Δ		*Carryforward flag
differential	16.48% <58.13%> (-0.26%)	⬇️
total	15.84% <ø> (ø)		Carriedforward from 56f4b7f

*This pull request uses carry forward flags. Click here to find out more.

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[youtalk]

Thank you for dividing PRs. It's much easier to review this.
In addition, could you provide some unit tests?

[youtalk]

The additional unit test was pass. https://github.com/autowarefoundation/autoware_lanelet2_extension/actions/runs/10467968639/job/28987828303?pr=22#step:7:385
Thank you for your cooperation. LGTM