ceph: update dashboard doc url to latest
ceph: update dashboard doc url to latest

ceph dashboard doc url in the doc is of older version. This patch updates it
with the latest doc url.

Signed-off-by: Varsha Rao <e55cb72a7d4117b8561feef3cb3020e66125c0b2@redhat.com>

rook/rook,rook/nfs,rook/rook,rook/nfs,rook/rook,rook/nfs,rook/rook,rook/rook