doc: Added admin tasks page for ceph-deploy.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added mds page for ceph-deploy.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added OSD page to ceph-deploy.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added purge page to ceph-deploy.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added transition from mkcephfs to ceph-deploy page.

fixes: #4756

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Updated index for new pages. Added inner table.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>
doc: Added reference to transition from mkcephfs to ceph-deploy.

Signed-off-by: John Wilkins <john.wilkins@inktank.com>