[#301] Move 'function' files to 'iox2/bb'

[elBoberido]

Notes for Reviewer

This PR moves the legacy::function to bb::StaticFunction

Pre-Review Checklist for the PR Author

• Add sensible notes for the reviewer
• PR title is short, expressive and meaningful
• Consider switching the PR to a draft (Convert to draft)
  • as draft PR, the CI will be skipped for pushes
• Relevant issues are linked in the References section
• Branch follows the naming format (iox2-123-introduce-posix-ipc-example)
• Commits messages are according to this guideline
  • Commit messages have the issue ID ([#123] Add posix ipc example)
  • Keep in mind to use the same email that was used to sign the Eclipse Contributor Agreement
• [~] Tests follow the best practice for testing
• [~] Changelog updated in the unreleased section including API breaking changes
• Assign PR to reviewer
• All checks have passed (except task-list-completed)

PR Reviewer Reminders

• Commits are properly organized and messages are according to the guideline
• Unit tests have been written for new behavior
• Public API is documented
• PR title describes the changes

References

Relates to #301

[codecov]

Codecov Report

❌ Patch coverage is 89.34426% with 13 lines in your changes missing coverage. Please review.
✅ Project coverage is 78.33%. Comparing base (d8f29d4) to head (f0af4aa).
⚠️ Report is 34 commits behind head on main.

Files with missing lines	Patch %	Lines
...-bb/cxx/include/iox2/bb/detail/static_function.hpp	88.57%	0 Missing and 12 partials ⚠️
.../cxx/include/iox2/legacy/cli/option_definition.hpp	0.00%	1 Missing ⚠️

Additional details and impacted files

@@           Coverage Diff           @@
##             main    #1218   +/-   ##
=======================================
  Coverage   78.32%   78.33%           
=======================================
  Files         413      410    -3     
  Lines       41023    40974   -49     
  Branches     1117     1113    -4     
=======================================
- Hits        32132    32095   -37     
+ Misses       8035     8025   -10     
+ Partials      856      854    -2     

Flag	Coverage Δ
CPP	72.25% <89.34%> (-0.15%)	⬇️
Rust	78.17% <91.59%> (+0.01%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Files with missing lines	Coverage Δ
iceoryx2-bb/cxx/include/iox2/legacy/string.hpp	100.00% <ø> (ø)
...yx2-cxx/include/iox2/internal/callback_context.hpp	51.85% <100.00%> (ø)
iceoryx2-cxx/include/iox2/listener.hpp	64.17% <100.00%> (ø)
iceoryx2-cxx/include/iox2/node.hpp	100.00% <ø> (ø)
iceoryx2-cxx/include/iox2/node_state.hpp	66.66% <ø> (ø)
...oryx2-cxx/include/iox2/port_factory_blackboard.hpp	66.66% <ø> (ø)
...xx/include/iox2/port_factory_publish_subscribe.hpp	67.50% <ø> (ø)
...cxx/include/iox2/port_factory_request_response.hpp	69.04% <ø> (ø)
iceoryx2-cxx/include/iox2/request_mut_uninit.hpp	87.50% <ø> (ø)
iceoryx2-cxx/include/iox2/response_mut_uninit.hpp	86.66% <ø> (ø)
... and 14 more

... and 6 files with indirect coverage changes

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