Link to passwords#new from change password view

www.agileplannerapp.com/boards/173808/cards/8676

following-up on the previous commit 17a185f, this change
adds link on the change password screen to sign-out the
current user so that they can request reset passphrase
instructions.
Integration tests to cover user flows

www.agileplannerapp.com/boards/173808/cards/8707