DRBD auto-promotes a resource to Primary during the provisioning path
(e.g. mkfs.ext4 against a freshly created replica), but auto-demote
sometimes fails to fire on close. The resource then stays Primary on
a node that has no consumer, and CSI on the legitimate target node
fails NodePublishVolume with "failed to set source device readwrite".
The only recovery is an explicit drbdadm secondary on the stuck node.

Add a per-satellite plunger handler that detects local Primaries
where every device has open == false and demotes them. Both the
detection and the action are local to the satellite, so no peer
coordination is needed. open:no makes drbdadm secondary safe; if a
real consumer is about to arrive, auto-promote will redo it.

Upstream tracker: piraeusdatastore/piraeus-operator#942

Co-Authored-By: Claude <[email protected]>
Signed-off-by: Andrei Kvapil <[email protected]>
(cherry picked from commit a6ac048)
(cherry picked from commit 44f9e49)