move some trust-related code to trust package

[thaJeztah]

cli/command/image: deprecate and internalize TrustedPush

This function was only used by "docker trust sign"; inline the code
and deprecate the function.

This function has no known external consumers, so we should remove
it on the first possible ocassion (which could be a minor release).

cli/command/image: deprecate PushTrustedReference, move to trust

This function was shared between "trust" "image" and "plugin" packages,
all of which needed the trust package, so move it there instead.

cli/command/image: deprecate TagTrusted, move to cli/trust

This function was shared between "image" and "container" packages,
all of which needed the trust package, so move it there instead.

- Human readable description for the release notes

Go SDK: cli/command/image: deprecate and internalize TrustedPush
Go SDK: cli/command/image: deprecate PushTrustedReference, move to trust
Go SDK: cli/command/image: deprecate TagTrusted, move to cli/trust

- A picture of a cute animal (not mandatory but encouraged)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 2.58621% with 113 lines in your changes missing coverage. Please review.

Project coverage is 59.29%. Comparing base (e558b91) to head (e37d814).
Report is 6 commits behind head on master.

❌ Your patch status has failed because the patch coverage (2.58%) is below the target coverage (50.00%). You can increase the patch coverage or adjust the target coverage.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #5894   +/-   ##
=======================================
  Coverage   59.28%   59.29%           
=======================================
  Files         355      357    +2     
  Lines       29758    29771   +13     
=======================================
+ Hits        17643    17653   +10     
- Misses      11143    11144    +1     
- Partials      972      974    +2     

🚀 New features to boost your workflow:

• ❄ Test Analytics: Detect flaky tests, report on failures, and find test suite problems.

[thaJeztah]

FWIW; there's a couple of changes I want to start making; I just had a look at the image references and formats we're using, and, even slightly simplified in my test, we're literally converting the image name 11 times, including juggling between a string, to a reference (various permutations), back to a string, before we even make a request with the engine 🫠

=== RUN   TestJuggleFormats
     STEP 1:  busybox (string)
     STEP 2:  docker.io/library/busybox (reference.repository)
     STEP 3:  docker.io/library/busybox:latest (reference.taggedReference)
     STEP 4:  docker.io/library/busybox:latest (string)
     STEP 5:  docker.io/library/busybox:latest (reference.taggedReference)
     STEP 6A: docker.io/library/busybox@sha256:498a000f370d8c37927118ed80afe8adc38d1edcbfc071627d17b25c88efcab0 (reference.canonicalReference)
     STEP 6B: docker.io/library/busybox:latest (reference.taggedReference)
     --> Tagging busybox@sha256:498a000f370d8c37927118ed80afe8adc38d1edcbfc071627d17b25c88efcab0 as busybox:latest
     STEP 7A: busybox@sha256:498a000f370d8c37927118ed80afe8adc38d1edcbfc071627d17b25c88efcab0 (string)
     STEP 7B: busybox:latest (string)
     STEP 8:  docker.io/library/busybox:latest (reference.taggedReference)
     STEP 9:  docker.io/library/busybox:latest (reference.taggedReference)
     --> SENDING TO DAEMON:  /images/busybox@sha256:498a000f370d8c37927118ed80afe8adc38d1edcbfc071627d17b25c88efcab0/tag?repo=busybox&tag=latest
     STEP 10: docker.io/library/busybox (reference.repository)
     STEP 11: docker.io/library/busybox:latest (reference.taggedReference)
     STEP 12: busybox (string)
     --> backend.GetImage
     --> backend.TagImage

[thaJeztah]

Looks like this introduced a regression; most likely because before this dockerCli.Client() would be initialised lazily, and it's possible some settings were loaded elsewhere.

I opened a PR that reverts some of the changes;

• cli/trust: TagTrusted: lazily request APIClient #5905

[thaJeztah]

Looks like reverting those changes (PR above) still makes things fail occasionally.

I think it's just a bad test and/or multiple tests affecting each other (perhaps using same port or otherwise)