mgr/rbd_support: recover from rados client blocklisting

mgr/rbd_support: recover from rados client blocklisting

In certain scenarios the OSDs were slow to process RBD requests.
This lead to the rbd_support module's RBD client not being able to
gracefully handover a RBD exclusive lock to another RBD client.
After the condition persisted for some time, the other RBD client
forcefully acquired the lock by blocklisting the rbd_support module's
RBD client, and consequently blocklisted the module's RADOS client. The
rbd_support module stopped working. To recover the module, the entire
mgr service had to be restarted which reloaded other mgr modules.

Instead of recovering the rbd_support module from client blocklisting
by being disruptive to other mgr modules, recover the module
automatically without restarting the mgr serivce. On client getting
blocklisted, shutdown the module's handlers and blocklisted client,
create a new rados client for the module, and start the new handlers.

Fixes: https://tracker.ceph.com/issues/56724
Signed-off-by: Ramana Raja <rraja@redhat.com>
(cherry picked from commit cc0468738e5ddb98f7ac10b50e54446197b9c9a0)