feat: Public GC function of oci.Store

[wangxiaoxuan273]

Part of #472

[codecov-commenter]

Codecov Report

Attention: 15 lines in your changes are missing coverage. Please review.

Comparison is base (c34d275) 75.57% compared to head (20af59f) 75.71%.

Files	Patch %	Lines
content/oci/oci.go	77.61%	10 Missing and 5 partials ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #656      +/-   ##
==========================================
+ Coverage   75.57%   75.71%   +0.13%     
==========================================
  Files          59       59              
  Lines        5692     5765      +73     
==========================================
+ Hits         4302     4365      +63     
- Misses       1023     1028       +5     
- Partials      367      372       +5     

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[eiffel-fl]

Hi!

This looks really cool!
I tested it and did not find any problem (I am still having blobs not deleted but I am thinking more and more this is because we are doing something wrong on our side).
I just have one comment regarding the TODO but nothing critical.

Best regards.

[eiffel-fl]

Hi!

I tested it and it works fine! I just found one small nit but unless I am missing something I think we are near the merge.

Best regards.

[eiffel-fl]

Hi!

I tested it and I like the new approach of using index.json!
I am still getting the same behavior but this is not related to this code (see #664).
I just found one small nit, otherwise, from my side, it is ready to go (note that I am not maintainer here, so just grey checkmark)!

Best regards.

[Wwwsylvia]

LGTM