webadmin: improve import conflict (for vm) dialog

The dialog which is shown when trying to import VM that already
exists in the system is modified:
1. the term "clone" was replaced with a string that better express what
happens during the cloning operation
2. the term "suffix:" was replaced with a string that better express
that the given string will be the suffix of the cloned VMs
2. the layout was changed to better reflect that the given new name is
related to the "import as cloned" option and "Suffix to add to the.." is
related to the "apply to all" option

Change-Id: Ia6fe863e52e9bad1d620bce75b8252bca4d0d414
Bug-Url: https://bugzilla.redhat.com/878495
Signed-off-by: Arik Hadas <ahadas@redhat.com>