Rename "Committers" to "Maintainers" to match CNCF's terminology

> > From the CNCF POV, project maintainers are people who can speak for the project and therefore should have access to everything (service desk, Maintainers mailing list, Copilot, etc).
> > [lima-vm/.project#1 (comment)](https://github.com/lima-vm/.project/issues/1#issuecomment-4817505191)
>
> "Maintainers" in containerd's terminology (which was inherited to Lima) has been inconsistent with that of CNCF, so I suggest changing the terminology:
>
> * Maintainers → Project Members? Community Members? Org Members?
> * Committers → Maintainers
> * Reviewers → Reviewers (as-is)? Maintainer Candidates?

_Originally posted by @AkihiroSuda in containerd/project#169_

Search the repository for uses of “Committers,” “Maintainers,” and “Reviewers” and read the surrounding project-governance context. Resolve the terminology mapping against the CNCF definitions referenced in the issue, then update every affected reference and verify that the old terminology is no longer used inconsistently.

Written by the indexing model from the issue text.