Add cosa build --force=image to only rebuild the image

[jlebon]

Feature Request

Desired Feature

A cosa build --force=image which disregards the image input check so we always rebuild the image. That way we don't have to keep faking it by e.g. editing image.yaml. Proposed in #741 (comment).

Example Usage

cosa build --force=image

[Prashanth684]

I'd like to take this on if nobody else is working on it.

[Prashanth684]

do we need to bother to support the short option "-f" with this change ? or should we remove the -f completely ?

[jlebon]

I don't think we should drop it. It should just keep meaning the same thing as --force (i.e. force an OSTree rebuild).

One thought related to this issue: I'm thinking it'd be better to just have a --force-image switch instead. The reason is that I think optional arguments are a pretty common footgun (i.e. --force=image vs. --force image).