[#390] waitset c binding

[elfenpiff]

Notes for Reviewer

The language bindings for C and C++. The C API is tested through the C++ API, which utilizes it fully.
The event-multiplexing example is not yet ported - this comes later.

Pre-Review Checklist for the PR Author

1. Add sensible notes for the reviewer
2. PR title is short, expressive and meaningful
3. Relevant issues are linked in the References section
4. Every source code file has a copyright header with SPDX-License-Identifier: Apache-2.0 OR MIT
5. Branch follows the naming format (iox2-123-introduce-posix-ipc-example)
6. Commits messages are according to this guideline
   • Commit messages have the issue ID ([#123] Add posix ipc example)
   • Commit author matches Eclipse Contributor Agreement (and ECA is signed)
7. Tests follow the best practice for testing
8. Changelog updated in the unreleased section including API breaking changes
9. Assign PR to reviewer
10. All checks have passed (except task-list-completed)

Checklist for the PR Reviewer

• 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

Post-review Checklist for the PR Author

1. All open points are addressed and tracked via issues

References

Relates to #390

[codecov]

Codecov Report

Attention: Patch coverage is 73.52941% with 9 lines in your changes missing coverage. Please review.

Project coverage is 79.03%. Comparing base (5904a48) to head (ce791a4).
Report is 37 commits behind head on main.

Files with missing lines	Patch %	Lines
iceoryx2/src/port/waitset.rs	72.72%	9 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #451      +/-   ##
==========================================
+ Coverage   79.00%   79.03%   +0.03%     
==========================================
  Files         196      196              
  Lines       23251    23373     +122     
==========================================
+ Hits        18369    18473     +104     
- Misses       4882     4900      +18     

Files with missing lines	Coverage Δ
iceoryx2-bb/posix/src/deadline_queue.rs	89.65% <ø> (ø)
iceoryx2-bb/posix/src/file_descriptor.rs	72.41% <ø> (ø)
iceoryx2/src/config.rs	70.21% <100.00%> (-5.91%)	⬇️
iceoryx2/src/port/waitset.rs	77.57% <72.72%> (-1.42%)	⬇️

... and 9 files with indirect coverage changes

[orecham]

Looks good, comments are mainly for superficial changes. The motivation, however, is to make the API as self-explanatory to future devs as possible by reducing the number of "cognitive steps" required to understand what is being done.

For example, with attach_notification, the question arises "what is a notification?", but this IMO is not information worth keeping track of when working with the WaitSet.