convert federation_members relation to real Entity

Until now there was simple relation ManyToMany between Provider and Federation entity.
For better control of membership it has been converted to proper entity FederationMembers
which also includes status of mebership , activity status, and ban status
Unfortunately this time update is not straighforward as doctrine-cli tool doesn't handle this situation well.

To make upgrade:
Make backup of DB and content.
log into mysql console and use your dbname and run:
ALTER TABLE federation_members ADD id INT AUTO_INCREMENT NOT NULL, ADD PRIMARY KEY (`id`);

then update code with : git pull
go to you Jagger instance into applications dir and run
./doctrine orm:schema-tool:update --force
./doctrine  orm:generate-proxies
set proper ownership (apache) for models/Proxies folder