Instead of configuring storage X by parameters in the main
section "X_class = backend" and "X_param = value", use a
new section in the config: "[storage:X]" and use "class =
backend" and "param = value" there.
This is the beginning, it includes a try at being backward
compatible. But that try isn't really fully useful anyway.
Factoring out this one should be the last one needed to
rewrite the celery setup. The idea is to not setup the
whole app, but just call a bunch of individual setup_*
functions and be done.
Setting up the database now involves checking the
migrations status and setting up the globals.
Moved all of that into init/__init__.py:setup_database().
The default name of the database ("mediagoblin") was coded
in db/open.py and init/celery/__init__.py.
Instead use the new config system to have this as the
default for the "db_name" config option.
