Add gui option for new branch property

@hackedbellini add the domain infrastructure for executing foreing work
orders in a previous patch. This is adding the gui option to set it in a
branch.

Change-Id: I2931a0de2696bb8bbcae1cb7bfa44e53a00a695e
Add associated field on optical medic

It is now possible to specify whether a medic is associated or not on
optical plugin. The field is also displayed on medic search and can be
filtered.

Previously added medics will be set as not associated

Change-Id: Idd8f208ddadad86112a3bb5a237f701e0ce71cea