spec: Multi-arch image management with ORAS

[FeynmanZhou]

What this PR does / why we need it:

Add a spec: Multi-arch image management with ORAS

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Fixes #1053

Preview: https://github.com/FeynmanZhou/oras/blob/multi-arch/docs/proposals/multi-arch-image-mgmt.md

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 84.37%. Comparing base (0abb460) to head (fb6e94d).

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1514      +/-   ##
==========================================
- Coverage   84.41%   84.37%   -0.04%     
==========================================
  Files         120      120              
  Lines        5460     5460              
==========================================
- Hits         4609     4607       -2     
- Misses        604      606       +2     
  Partials      247      247              

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[shizhMSFT]

To make the spec more professional, please proofread the spec and fix formatting issues.

[shizhMSFT]

LGTM but you need to fix the check failure.

[tarilabs]

thank you for drawing my attention to this, @FeynmanZhou ! 🙏

some very optional comments below, I hope these helps!

[TerryHowe]

Maybe add your svgs to https://github.com/oras-project/oras/blob/main/.github/licenserc.yml#L31

[FeynmanZhou]

Maybe add your svgs to https://github.com/oras-project/oras/blob/main/.github/licenserc.yml#L31

Raised a PR to address this issue: #1619

[TerryHowe]

I updated the branch and tests are passing now.

[Wwwsylvia]

LGTM

[sudo-bmitch]

The comment suggesting that various tools do not provide native support for local environment I believe is a reference to the current stable docker engine. There are changes coming with docker, and it's inaccurate with many of the other tools described. https://docs.docker.com/desktop/features/containerd/