Draft: munin: use the plugins provided by debci

Since debci commit 7d6f448, these plugins now live in that package, so we can stop installing them from this repo. I think we still need to link them.

Follow up from merge request: debci!256 (merged)

Untested, but I think we want something like this.

Grmbl... This very close to exactly the same as !17 (merged).

closed