Documentation: nfs: pnfs-scsi-server: convert to ReST

Convert pnfs-scsi-server to ReST and move it to admin-guide. Content
remains mostly unchanged.
Signed-off-by: NDaniel W. S. Almeida <dwlsalmeida@gmail.com>
Link: https://lore.kernel.org/r/5c4b8af41ca0a427a3987535815bccf47a65d320.1578697871.git.dwlsalmeida@gmail.comSigned-off-by: NJonathan Corbet <corbet@lwn.net>

Documentation/admin-guide/nfs/index.rst

@@ -11,3 +11,4 @@ NFS
     nfsd-admin-interfaces
     nfs-idmapper
     pnfs-block-server
+    pnfs-scsi-server

Documentation/filesystems/nfs/pnfs-scsi-server.txt → Documentation/admin-guide/nfs/pnfs-scsi-server.rst

 
+==================================
 pNFS SCSI layout server user guide
 ==================================