Flavor ID added to Flavor creation form

Flavor ID supported values are:
* integer
* uuid4
* auto

Using 'auto' generates a random uuid4.

Clean method from Edit Form removed as unnecessary.

Flavor tests updated.

Fixes: bug #1189877

Change-Id: I222836d7a84b66891d5380f323bf123122044d30
Merge "Flavor ID added to Flavor creation form"