remove user and role auth, consolidate some related code

On several occasions while testing the agent on different systems with the master deployed alongside I ran into issues while trying to get the web ui started with regards to the requirement of having an initial admin user.  Rather than spending the time to try to fix this problem for a third time I've opted to remove the user login and role requirement behind the web ui.  I think this is the best course of action because the current system is incomplete, insecure, and will more than likely be replaced at some point.

As a result of these changes the general code behind the web views becomes a little simpler and we can drop four tables from the database since they'll no longer be used by anything.  In addition this pull request has a few other related changes too:

* Removes the /setup/ endpoint.  This was used to create the database tables and create an admin user.  Creating an admin user is no longer necessary and creation of the tables is better handled by a simple script.
* Removes flask-login as a requirement.  This was only used for getting the user logged in and constructing their session since this pull request removes these this library is no longer needed.
* Always calls `db.create_all()` before the first request if we're working with an in memory sqlite database.  This was handled by /setup/ but it was unreliable and it's something we can just assume we have to do before the first request.
* Replace the `pyfarm-dev-dbdata` script with `pyfarm-create-tables`.  `pyfarm-dev-dbdata` was out of date and now that the agent has starting to talking to the master `pyfarm-create-tables` is not really necessary.  We do however need a general way to create missing tables however so `pyfarm-create-tables` was created.
* Consolidates `pyfarm.master.entrypoints` into a single package.  After this pull request there was only a few lines of code in `entrypoints.dev`  and `entrypoints.users` had already been removed since it was no longer in use.