[#96] decentral service artifact cleanup

[elfenpiff]

Notes for Reviewer

• Cleaned up a technical debt, FilePath::path() and FilePath::file_name() are returning a Path or FileName and no longer a slice. Makes it easier to use since it prevents either addition checks or unsafe sections. In some files, those unsafe sections were removed.
• Introduces process_state.rs in posix, a basic building block to enable process monitoring. When this is merged, a concept in iceoryx2_cal called Monitor will be introduced that will use this and provides a safe user API.

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
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

Use either 'Closes #123' or 'Relates to #123' to reference the corresponding issue.

Relates to #96

[codecov]

Codecov Report

Attention: 147 lines in your changes are missing coverage. Please review.

Comparison is base (cd4211a) 77.94% compared to head (a3bd5b3) 77.64%.
Report is 4 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main      #97      +/-   ##
==========================================
- Coverage   77.94%   77.64%   -0.31%     
==========================================
  Files         177      178       +1     
  Lines       18881    19222     +341     
==========================================
+ Hits        14716    14924     +208     
- Misses       4165     4298     +133     

Files	Coverage Δ
iceoryx2-bb/posix/src/config.rs	3.75% <ø> (ø)
iceoryx2-bb/system-types/src/file_name.rs	69.56% <100.00%> (+13.04%)	⬆️
iceoryx2-bb/system-types/src/file_path.rs	84.81% <100.00%> (-0.38%)	⬇️
iceoryx2-bb/system-types/src/group_name.rs	100.00% <100.00%> (+18.75%)	⬆️
iceoryx2-bb/system-types/src/user_name.rs	100.00% <100.00%> (+18.75%)	⬆️
...yx2-cal/src/communication_channel/message_queue.rs	78.70% <100.00%> (-0.23%)	⬇️
iceoryx2-cal/src/communication_channel/mod.rs	53.84% <ø> (ø)
iceoryx2-cal/src/dynamic_storage/mod.rs	100.00% <ø> (ø)
...yx2-cal/src/dynamic_storage/posix_shared_memory.rs	93.29% <100.00%> (-0.07%)	⬇️
iceoryx2-cal/src/event/mod.rs	26.31% <ø> (ø)
... and 11 more

... and 3 files with indirect coverage changes

[elBoberido]

The process_state.rs and its tests are something for tomorrow

[elBoberido]

I need to create a sequence diagram with all the things that could happen during a race between the application and the monitoring process. I somehow have the feeling that it is quite racy and especially when you start multiple applications at once, including the monitoring application, this could lead to unexpected results.

[elBoberido]

An interim review. Need to finish process_state_tests.rs

[elBoberido]

Tests look good.

I'm just not sure if the terminology for the file names should be changed to something more generic than .cleaner, e.g. .owner_lock. It acts more or less as the lock file in iceoryx1.

Nothing to block this PR but something to think about.