feat: support formatted output in oras attach and push

[qweeah]

What this PR does / why we need it:
This PR introduces --format flag to command oras push and oras attach. UX would be like:

$  subject=`oras push localhost:5000/test:demo --format {{.Ref}}`
✓ Exists    application/vnd.oci.empty.v1+json                                                                                                                                                                                                              2/2  B 100.00%     0s
  └─ sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a
✓ Uploaded  application/vnd.oci.image.manifest.v1+json                                                                                                                                                                                                 535/535  B 100.00%     0s
  └─ sha256:277450c0be1aa8c684eeaa3fb128d3ac29c7c7e7add45971436b5bb785076abc
$ oras attach $subject --artifact-type test/example -a k=v --format json
✓ Exists    application/vnd.oci.empty.v1+json                                                                                                                                                                                                              2/2  B 100.00%     0s
  └─ sha256:44136fa355b3678a1146ad16f7e8649e94fb4fc21fe77e8310c060f61caaff8a
✓ Uploaded  application/vnd.oci.image.manifest.v1+json                                                                                                                                                                                                 683/683  B 100.00%     0s
  └─ sha256:a3d50fbe69ca09d6b04a65262b33a6ec524e5d8c626b5f8378f329e605f8e53b
{
  "Ref": "localhost:5000/test@sha256:a3d50fbe69ca09d6b04a65262b33a6ec524e5d8c626b5f8378f329e605f8e53b",
  "MediaType": "application/vnd.oci.image.manifest.v1+json",
  "Digest": "sha256:a3d50fbe69ca09d6b04a65262b33a6ec524e5d8c626b5f8378f329e605f8e53b",
  "Size": 683,
  "URLs": null,
  "Annotations": {
    "k": "v",
    "org.opencontainers.image.created": "2024-01-09T09:01:11Z"
  },
  "Data": null,
  "Platform": null,
  "ArtifactType": ""
}%       

Which issue(s) this PR fixes (optional, in fixes #<issue number>(, fixes #<issue_number>, ...) format, will close the issue(s) when PR gets merged):
Related to #638

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: 48 lines in your changes are missing coverage. Please review.

Comparison is base (22c59ef) 81.35% compared to head (9fd97e9) 81.97%.

Files	Patch %	Lines
cmd/oras/root/push.go	46.15%	4 Missing and 3 partials ⚠️
cmd/oras/internal/display/handler.go	83.33%	2 Missing and 4 partials ⚠️
cmd/oras/internal/display/status/tty.go	83.33%	4 Missing and 2 partials ⚠️
cmd/oras/root/file.go	28.57%	3 Missing and 2 partials ⚠️
cmd/oras/internal/option/format.go	55.55%	3 Missing and 1 partial ⚠️
cmd/oras/root/manifest/push.go	20.00%	1 Missing and 3 partials ⚠️
...ras/internal/display/metadata/template/template.go	50.00%	2 Missing and 1 partial ⚠️
cmd/oras/internal/display/metadata/text/attach.go	76.92%	2 Missing and 1 partial ⚠️
cmd/oras/internal/display/status/text.go	92.10%	2 Missing and 1 partial ⚠️
cmd/oras/root/cp.go	57.14%	0 Missing and 3 partials ⚠️
... and 3 more

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #1237      +/-   ##
==========================================
+ Coverage   81.35%   81.97%   +0.61%     
==========================================
  Files          68       83      +15     
  Lines        3825     3995     +170     
==========================================
+ Hits         3112     3275     +163     
+ Misses        500      497       -3     
- Partials      213      223      +10     

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[shizhMSFT]

LGTM

[shizhMSFT]

LGTM

[shizhMSFT]

LGTM

[shizhMSFT]

LGTM

[shizhMSFT]

LGTM