webadmin: Add checkbox for format when remove Storage domain

Add format checkbox when remove a data Storage Doman.
The checkbox should be checked for Data Storage Domain since most of the
use cases should be formatting it.

Change-Id: Ia844883ebca19be9c4f6a26f7c34b3423bf0f2d3
Bug-Url: https://bugzilla.redhat.com/1138132
Signed-off-by: Maor Lipchuk <mlipchuk@redhat.com>