RPC info should include comaintainers

• I have summed up the feature in concise words in the Summary section.
• I have completely described the feature in the Description section.
• I have completed the Blockers section.

Summary

The AUR RPC interface could return the list of co-maintainers in info queries.

Description

As far as I can see the AUR RPC interface currently only returns the regular maintainer of a package in the Maintainer field of info responses. It'd be handy to also have access to the list of additional co-maintainers, e.g. in a separate CoMaintainers field.

I'm trying to automate trust checking for AURs (i.e. automatically build packages maintained by a list of trusted user accounts), but without information about co-maintainers this trust check is incomplete at best. It'd be great to have a full list of user accounts permitted to push to an AUR package in the info endpoint.