c8d: Add --platform flag to history, save and load

[vvoland]

• needs: c8d: Add platform parameter to history, save and load moby/moby#48295
• needs: vendor: github.com/docker/docker 164cae56ed95 (master, v-next) #5428

Add --platform flag to history, save and load.

- Description for the changelog

containerd image store: `docker load` and `docker save` now support a `--platform` flag allowing to choose a specific single-platform image to load/save if the image is multi-platform
containerd image store: `docker history` now supports a `--platform` flag allowing to choose a specific platform to show the history for.

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

[dvdksn]

How about including the full cmd?

Suggested change

	Example: "linux/amd64"`)
	Example: "docker image history --platform linux/amd64"`)

[thaJeztah]

I (somewhat) assume that this was done to allow defining a global const for these flags and for them to be shared (similar to what we did for --format 🤔), but I need to check if they differ in other ways

[dvdksn]

Suggested change

	`Pick a single-platform to be loaded if the image is multi-platform.
	Full multi-platform image will be load if not specified.
	Format: os[/arch[/variant]]
	Example: "linux/amd64"`)
	`Specify a platform from a multi-platform image to load.
	If a platform is not specified, and the image is a multi-platform image, all platforms are loaded.
	Format: os[/arch[/variant]]
	Example: "docker image load --platform linux/amd64"`)

[dvdksn]

Suggested change

	`Pick a single-platform to be saved if the image is multi-platform.
	Full multi-platform image will be saved if not specified.
	Format: os[/arch[/variant]]
	Example: "linux/amd64"`)
	`Specify a platform from a multi-platform image to save.
	If a platform is not specified, and the image is a multi-platform image, all platform variants are saved.
	Format: os[/arch[/variant]]
	Example: "docker image save --platform linux/amd64"`)

[codecov-commenter]

Codecov Report

Attention: Patch coverage is 53.84615% with 18 lines in your changes missing coverage. Please review.

Project coverage is 59.73%. Comparing base (3a3fe84) to head (8ebf4cf).

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #5331      +/-   ##
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- Coverage   59.74%   59.73%   -0.02%     
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  Files         345      345              
  Lines       23432    23469      +37     
==========================================
+ Hits        14000    14019      +19     
- Misses       8458     8473      +15     
- Partials      974      977       +3     

[thaJeztah]

@dvdksn I applied your suggestions; I'm slightly wondering if we should / could condense the information a bit; for example;

Specify a platform -> Platform from a multi-platform image ...

(I don't think we generally add Specify .... as that's a bit implicit for options?)

The "format" could possibly be included in the first line, something like;

Platform from a multi-platform image to show the history for (format: "os[/arch[/variant]]")

By default, the daemon's native platform is preferred, otherwise any available platform is used.

(wondering if the host platform is ambiguous, and if we need to emphasise daemon platform)