docs/devel: add a maintainers section to development process

We don't currently have a clear place in the documentation to describe
the roles and responsibilities of a maintainer. Lets create one so we
can. I've moved a few small bits out of other files to try and keep
everything in one place.

Signed-off-by: Alex Bennée <alex.bennee@linaro.org>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Reviewed-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Message-Id: <20221117172532.538149-5-alex.bennee@linaro.org>
diff --git a/MAINTAINERS b/MAINTAINERS
index be151f0..366538f 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -23,7 +23,7 @@
 	W: Web-page with status/info
 	Q: Patchwork web based patch tracking system site
 	T: SCM tree type and location.  Type is one of: git, hg, quilt, stgit.
-	S: Status, one of the following:
+	S: Status, one of the following (keep in sync with docs/devel/maintainers.rst):
 	   Supported:	Someone is actually paid to look after this.
 	   Maintained:	Someone actually looks after it.
 	   Odd Fixes:	It has a maintainer but they don't have time to do