[#1742] Implement ros2 tunnel send path

[orecham]

Notes for Reviewer

Implements the send path for the ROS 2 tunnel backend.

Remaining capabilities and CI to be merged in subsequent pull requests. See the README in integrations/ros2/tunnel-backend for the development status.

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• Add sensible notes for the reviewer
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• Relevant issues are linked in the References section
• Branch follows the naming format (iox2-123-introduce-posix-ipc-example)
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References

Closes #1742

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 76.21%. Comparing base (22c4239) to head (961d184).
⚠️ Report is 59 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1744      +/-   ##
==========================================
- Coverage   76.25%   76.21%   -0.05%     
==========================================
  Files         430      429       -1     
  Lines       42701    42684      -17     
  Branches     1327     1329       +2     
==========================================
- Hits        32562    32530      -32     
- Misses       9054     9066      +12     
- Partials     1085     1088       +3     

Flag	Coverage Δ
CPP	63.29% <ø> (+0.06%)	⬆️
Rust	76.08% <ø> (-0.05%)	⬇️

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

Files with missing lines	Coverage Δ
iceoryx2-services/tunnel-backend/src/types/wake.rs	0.00% <ø> (ø)

... and 24 files with indirect coverage changes

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[elfenpiff]

Please do not implement Clone for a shallow clone.

In my opinion, it is cleaner when everyone, who requires the type support to be alive uses the Rc<TypeSupportInner> struct. Otherwise, one might think that two distinct TypeSupport instances are alive whilst there is just one.

[orecham]

@elfenpiff I don't really follow your point. This is just a "handle to the type support".

[elfenpiff]

Since we have two different views here, could we agree that @elBoberido solves the tie?

[orecham]

This is just a minimal wrapper of rcl only for use by the tunnel. Is it worth to spend more time here? We can change it later.

[elBoberido]

A little bit late to the party, but I would also prefer to have a Rc<TypeSupportInner>/Rc<TypeSupport> instead of hiding the Rc in a wrapper.

[orecham]

@elBoberido @elfenpiff I will revise it all later, let me get the functionality in, then I will do some additional iterations to make it pretty and conventional. I cannot do both at once 🫠 .