webadmin: Template name restricted to 40 characters for all OS

Fixed validation of create/edit template name validation.
VM name is restricted to 15 characters for Windows host, 64 characters for other hosts.
VM template name is max. 40 characters long.

Change-Id: Id7bb03dea4c6030a485f0d60d775dd308c4c7155
Bug-Url: https://bugzilla.redhat.com/848398
Signed-off-by: Libor Spevak <lspevak@redhat.com>