Proposal to make it possible to create images for another platform

[shawjef3]

It's possible to specify the platform for a container by using GenericContainer#withCreateContainerCmdModifier.
However, it's not possible to do the same when creating an image, and so it's
not possible to both create and test an image for a platform.

Add ImageFromDockerfile#withBuildImageCmdModifier which will make this possible.

This is implemented by #7313.

[shawjef3]

I see that it's possible to do this by overriding ImageFromDockerfile#configure, but that's super not obvious, and requires making a a new class for something that's just a parameter in GenericContainer.

[eddumelendez]

Don't you think it's a little bit late to open a discussion due to there is a PR already open? :) See our docs for contributing

[shawjef3]

I read the docs for contributing. Can you please link to the PR? I searched them for a couple keywords and it wasn't obvious to me.

EDIT: I'm assuming you aren't talking about my PR since you closed my associated issue.

[eddumelendez]

I was talking about yours :)

[shawjef3]

Okay. I'll just wait for a code review then. I was trying to retroactively follow the guidelines but I guess that's not required.