mgr/dashboard: Rbd Mirroring improvements

mgr/dashboard: Rbd Mirroring improvements

1.RBD images in dashboard shows default mirroring as journal
2.snapshot based mirroring schedule Interval got disabled to edit
3.unable to create snapshot of an image using dashboard
4.provide snapshot schedule info in a new column
5.dashboard doesn't allow importing peer bootstrap key to be imported for subsequent pools

Fixes: https://tracker.ceph.com/issues/58297
Signed-off-by: Aashish Sharma <aasharma@redhat.com>
(cherry picked from commit 1a37c5e001e0bbc2720e6dfabf6ba04442acabb7)