Change buf beta registry label archive/unarchive to buf beta registry archive/unarchive

[doriable]

This PR changes buf beta registry label archive/unarchive to
buf beta registry archive/unarchive, which is able to take a
workspace input and archive/unarchive all labels for modules
in the workspace.
This UX change is needed to support uses-cases such as
GitHub Actions.

[saquibmian]

My comments are mostly about the command's docs; otherwise looks good.

[saquibmian]

I wonder if we should consider target modules in the workspace as well. The Archive/Unarchive RPCs currently does not allow archiving/unarchiving labels that don't exist. Does that pose a problem where the user would like to archive a label that only exists for some modules in the workspace but not for others?

[doriable]

Does that pose a problem where the user would like to archive a label that only exists for some modules in the workspace but not for others?

I tried to bring this up yesterday, but I think it got a little lost. Right now the behaviour would be that this would error, since it's a single RPC call (per registry, but everything should be from the same registry), and I think this is a pretty reasonable behaviour. We are disallowing this for v1 workspaces, and so users with v1 workspaces would still need to continue with the workflows they already have to manage each individual module. This will start coming up for v2 workspaces, but I am okay with launching with the behaviour of error-ing and then going from there. But open to other's thoughts on this.

[nicksnyder]

I think matching the API behavior here is fine since the alternative is just to target the specific modules that have the label you want to archive.