feat(referrers): delete manifest with subject

[pat-pan]

What this PR does / why we need it

The PR is to implement the feature to delete manifest with subject as per the OCI distribution spec v1.1.0.

Which issue(s) this PR resolves / fixes

Resolves / Fixes #160

Please check the following list

• Does the affected code have corresponding tests, e.g. unit test, E2E test?
• Does this change require a documentation update?
• Does this introduce breaking changes that would require an announcement or bumping the major version?
• Do all new files have an appropriate license header?

[codecov]

Codecov Report

Attention: Patch coverage is 88.97638% with 14 lines in your changes missing coverage. Please review.

Project coverage is 83.79%. Comparing base (1ac218a) to head (90cb141).
Report is 1 commits behind head on main.

Files with missing lines	Patch %	Lines
.../OrasProject.Oras/Registry/Remote/ManifestStore.cs	81.57%	3 Missing and 4 partials ⚠️
src/OrasProject.Oras/Registry/Reference.cs	66.66%	2 Missing and 1 partial ⚠️
src/OrasProject.Oras/Registry/Remote/Repository.cs	91.66%	2 Missing and 1 partial ⚠️
...sProject.Oras/Registry/Remote/ResponseException.cs	95.23%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main     #174      +/-   ##
==========================================
+ Coverage   83.25%   83.79%   +0.54%     
==========================================
  Files          37       38       +1     
  Lines        1266     1370     +104     
  Branches      149      165      +16     
==========================================
+ Hits         1054     1148      +94     
- Misses        149      155       +6     
- Partials       63       67       +4     

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[Wwwsylvia]

LGTM

[shizhMSFT]

LGTM