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>
deploy: Support run command

..to kinda simulate pdsh. Specifically:

  snf-deploy run --setup synnefo --cmd "apt-get update" -vvv

or:

  snf-deploy run --target-nodes node1,node2 --cmd "apt-get update"

Signed-off-by: Dimitris Aragiorgis <dimara@grnet.gr>
cyclades: Support shared-filer ext provider

Pass origin disk parameter and img_id None only if provider
is included in GANETI_CLONE_PROVIDER list.

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