feat: better composite action

[AtomicFS]

I am really annoyed by the amount of necessary copy-pasting when using firmware-action in GitHub CI. For some complex firmware stacks, when users want various combinations and use multiple matrix strategies, this complexity explodes quite fast. And most of the workflow then is just cache upload, cache download, artifact upload, artifact download.

This PR is addressing this. However because GitHub CI has a lot of limitations, and many questionable design decisions, it is not straight forward process. Maybe one way would be to implement GitHub API interface, but I do not want o make that nor maintain that. More rant and details in action.yml comments. Also see #84 for more information (== more rant).

Must be merged after #592

To function, this PR relies on features introduced in #603

This PR is rather a big deal

It changes significant parts which did not change for a long time. I don't think it will break anything, but we should test this before deploying.

As such, this change should be just drop-in replacement, it should still work even if users do not change anything. The example tests that we are running seem to work fine after some cleanup of redundant code.

Besides these example tests I am also trying it out in firmware-action-example PR. As you can see there, this PR poses a significant simplification and reduction of code needed in the workflow. For example of functional multi-job workflow see run 13686309056

Fixes #84

[pointbazaar]

Should be good to go with a few small changes.

Comments are mostly about not adding options unless they are required,
and naming options with prefixes to make them easier to group and understand
which wrapped action they will go into.

I really like the migration guide which will be very helpful to users.

[pointbazaar]

Ok, if some of the options are just passed to upload-artifact and download-artifact in a transparent way, then it is fine, since we are not adding any feature there.
Might have gone overboard a little with my preference for simplification in my last review.

I see the prefix has been added to clarify this for the user.
To further clarify, we can remove all documentation of the flags passed to
the upload and download actions, and just link to their respective documentation.

This should be easier for the user, since the information is not duplicated.
I think then it should be good to go 👍🏼

[AtomicFS]

@pointbazaar I actually did forgot one option, just added it for completion.

[pointbazaar]

Looks good to me.

• nice prefix for all the flags related to a wrapped action
• link to the docs of the wrapped action
• documentation of which version of that action is being wrapped

👍🏼

[AtomicFS]

@MDr164 your approval is still required since you are the owner.