feat: add breadcrumb ringbuffer to avoid O(n) memmove

[JoshuaMoelans]

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

(in progress)

• [x] Creating ringbuffer
• [x] Storing items to ringbuffer
• [x] Rethink decref test -> add a test that checks reference counts of objects added/overwritten in ringbuffer
• [x] Extracting items from ringbuffer (by converting back to regular list)
• [ ] Updating docs
• [x] 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

```diff @@ 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 ```