refactor(lanelet2_extension): move RegisterRegulatoryElement to cpp file

[isamu-takagi]

Description

To register a class, put
RegisterRegulatoryElement regMyClass;
somewhere in your cpp file.

Follow this comment to move RegisterRegulatoryElement to cpp file. Also, remove redundant namespace and move the constructor to match the comment about object creation.

Related links

None

Tests performed

Check if lanelet2 map can be loaded using simple planning simulator.

Notes for reviewers

None

Interface changes

None

Effects on system behavior

None

Pre-review checklist for the PR author

The PR author must check the checkboxes below when creating the PR.

• I've confirmed the contribution guidelines.
• The PR follows the pull request guidelines.

In-review checklist for the PR reviewers

The PR reviewers must check the checkboxes below before approval.

• The PR follows the pull request guidelines.
• The PR has been properly tested.
• The PR has been reviewed by the code owners.

Post-review checklist for the PR author

The PR author must check the checkboxes below before merging.

• There are no open discussions or they are tracked via tickets.
• The PR is ready for merge.

After all checkboxes are checked, anyone who has write access can merge the PR.

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (3a04b3f) 11.11% compared to head (d7c22bb) 11.11%.
Report is 1 commits behind head on main.

❗ Current head d7c22bb differs from pull request most recent head f7c5d7d. Consider uploading reports for the commit f7c5d7d to get more accurate results

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #222      +/-   ##
==========================================
- Coverage   11.11%   11.11%   -0.01%     
==========================================
  Files          37       37              
  Lines        2708     2709       +1     
  Branches     1387     1388       +1     
==========================================
  Hits          301      301              
  Misses       1987     1987              
- Partials      420      421       +1     

Flag	Coverage Δ		*Carryforward flag
differential	9.46% <ø> (?)
total	11.35% <ø> (+0.24%)	⬆️	Carriedforward from 1ef21e6

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

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[kosuke55]

LGTM!