docs: add docs for cephfs

- specifically related to managing csi volumes for kubernetes

doc/ceph/README.md

@@ -78,7 +78,7 @@ Create a key with access to the new subvolume groups. Check if the user already
 
 If it doesnt:
 
-sudo ceph auth get-or-create client.kubernetes-cephfs \
+    sudo ceph auth get-or-create client.kubernetes-cephfs \
       mgr 'allow rw' \
       osd 'allow rw tag cephfs metadata=cephfs, allow rw tag cephfs data=cephfs' \
       mds 'allow r fsname=cephfs path=/volumes, allow rws fsname=cephfs path=/volumes/csi_ssd_ec_6_2, allow rws fsname=cephfs path=/volumes/csi_ssd_ec_4_1' \