Improve labels in change password interface

I received complaints from admin users trying to change other users' password that it was confusing because when say admin user "A" selects a user "B" under "Users" and then clicks "Change Password", the first label says

"Current password for the user "A""

Resulting in them questioning whether they're changing the password for "A" or for "B". Hope that explanation made sense :) Anyway, this is a proposed patch that simply makes it explicit by changing the label for the second field from just "Password" to

"New password for the user "B""

My company is experimenting with moving to Kanboard for project/task management and I'll be doing some patching to help fit my company's needs. I'll be sending pull requests to hopefully have most of them upstreamed :)