Cleanup Client login logic

[nazar]

Related to #43.

Tasks

1. Refactor the top level client login, callback and almost-finished routes into a single login view with the callback and almost-finished as sub-routes.

2. Refactor this block of code to only be called in the new login/callback component as currently the Promise in the block of code never fulfils as the lock.on events only trigger durring the auth0 callback. Instead attempt to use webAuth.checkSession to auto login the user if their auth0 session is still active.