deploy: Add missing cyclades options for ext

The ext disk template needs some extra parameters that are defined
in cyclades settings. Add those missing settings.

Additionally remove any hardcoded references to /srv/ganeti since this
is configurable.

Change mails found in cyclades.conf to examples (e.g
user@synnefo.org).

Add shared-filer ext provider too (by installing ExtStorage
component too).

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>