New script `idesl-mdstat`.

Compare the Linux actual MD RAID status (as reported by
`/proc/mdstat`) with the one configured in
`/usr/local/etc/mdadm.conf.ESPFS`.

In the present state, the script is likely only useful on the UZH
Schroedinger cluster Lustre servers.
New `adduser.sh` script to create users on the GC3/UZH LDAP servers.

Very local thing. Might be removed in the future as the last thing the
world needs is yet another add-user script.
adduser.sh: Set ownership on home dir and all its subdirectories.
Rename `adduser.sh` to `gc3-adduser`.