Move the forms specific to local login into their own file
Adjust the login controller to use the login_forms instead of regular forms
Add a get_site_by_name method to the internal API
Add the `uploaded_config` method to the internal API

This method is used when mirrors upload their own pickle file with all
the information about the data they contain.
Add the hostconfig file in the internal library

This is the file used to check the validity of the configuration file
submitted by a mirror and update its pickle if the configuration file is
valid.

This file is used via the xmlrpc interface.
Add the xml-rpc controller for MirrorManager2

This xml-rpc controller is required by report_mirror, a client script
used by private mirrors to report their status and thus let the server
include them in the list used by yum
Activate the xmlrpc controller in the flask application

Signed-off-by: Pierre-Yves Chibon <pingou@pingoured.fr>
Add requirement to flask-xml-rpc