Add column and field "DNS Priority" to Static NAT Entry when DNS NAT Method is Priority

Add two options: hidden_condition, hide_list_condition

   hidden_condition will call function by the model path string be parsed. If it return True, then hidden_condition will be False.

   Then the fields will be hidden when Popup window show for New or Edit.

   hide_list_condition will call function by the model path string be parsed. If it return True, then hide_list_condition will be True.

   Then the column will be hidden in the table(list).
Add method "priority" to NATProtocolSettings class
Add field "priority" to StaticNATEntry class and set it default 0 and range hint is 1 to 512, hide column or fields by function call (parsed string)
Add update priority function
Add vip and priority mapping function
Handle language for DNS Priority column and field.
Remove some spaces in files.