Add Select Partner on 1st step dataset

Add "Select Partner" dropdown list at 1st step of Dataset Registration

Following our discussion with @mobreza I'm creating several tickets

Dropdown list should contain list of partners to whom the user is attached.

Opt. if doesn't require much effort. In case user belongs to only 1 partner, selection should be disabled.

Edited Nov 15, 2017 by Oleg Kalmykov