refactor: add metadata render interface and apply it to oras attach command

[wangxiaoxuan273]

What this PR does / why we need it:

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Part of #1573

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

All modified and coverable lines are covered by tests ✅

Project coverage is 84.33%. Comparing base (0844004) to head (36dcba1).
Report is 1 commits behind head on main.

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1578      +/-   ##
==========================================
+ Coverage   84.29%   84.33%   +0.03%     
==========================================
  Files         120      120              
  Lines        5401     5413      +12     
==========================================
+ Hits         4553     4565      +12     
  Misses        602      602              
  Partials      246      246              

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[qweeah]

LGTM