Allowing account to be unlocked from the edit page

https://www.agileplannerapp.com/boards/173808/cards/4276

the users listing was the only place from where
the account could be unlocked. trying to bring
more user related admin actions on the edit page.

i've also unified the look and feel of Unlock buttons
based on inputs from @fofr.
Merge pull request #231 from alphagov/show-unlock-link-on-edit-page

Allowing account to be unlocked from the edit page