Optimize SHM metadata storage (adds ~300k msgs\sec)

[yellowhatter]

No description provided.

[YuanYuYuan]

The change looks good to me, except for the choice of LinkedList rather than VecDeque.

[YuanYuYuan]

Feel free to merge once the CI completes.

[codecov]

Codecov Report

❌ Patch coverage is 75.00000% with 2 lines in your changes missing coverage. Please review.
✅ Project coverage is 70.85%. Comparing base (b6cb64a) to head (582b8c5).
⚠️ Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
commons/zenoh-shm/src/metadata/descriptor.rs	0.00%	1 Missing ⚠️
commons/zenoh-shm/src/metadata/storage.rs	85.71%	1 Missing ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #2116      +/-   ##
==========================================
+ Coverage   70.82%   70.85%   +0.02%     
==========================================
  Files         373      373              
  Lines       63157    63156       -1     
==========================================
+ Hits        44734    44751      +17     
+ Misses      18423    18405      -18     

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