Split admin org edit people reorder

Moving this out halves the time to update the db for BIS and also removed confusion of not being able to reorder people on the peoples tab on organisations.

Not sure this will fix the Mysql2::Error: Lock wait timeout exceeded on BIS as I've not been able to replicate it on my VM but we can see if it helps.

https://www.pivotaltracker.com/story/show/46971305