Add breadcrumb ringbuffer to avoid O(n) memmove

[JoshuaMoelans]

Fixes https://github.com/getsentry/sentry-native/issues/1006

(in progress)

• [x] Creating ringbuffer
• [ ] Storing items to ringbuffer -> works for breadcrumbs, but 2 tests fail (don't match the new logic) -> ToDo - rethink tests; are they expected behaviour?
• [ ] Extracting items from ringbuffer -> find out where these get accessed
• [ ] Updating docs
• [ ] Updating changelog

[github-actions[bot]]

	Messages
:book:	Do not forget to update Sentry-docs with your feature once the pull request gets approved.

Generated by :no_entry_sign: dangerJS against 190a4a5d1dc195d5b038634f83902f79c8e84b0b

[codecov[bot]]

Codecov Report

Attention: Patch coverage is 83.78378% with 6 lines in your changes missing coverage. Please review.

Project coverage is 82.60%. Comparing base (b598af0) to head (190a4a5). Report is 3 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1060      +/-   ##
==========================================
- Coverage   82.63%   82.60%   -0.04%     
==========================================
  Files          53       53              
  Lines        7660     7680      +20     
  Branches     1208     1209       +1     
==========================================
+ Hits         6330     6344      +14     
- Misses       1216     1224       +8     
+ Partials      114      112       -2