Documentation: add a note to set mysql's root password
Set real default keys' names otherwise an error will be raised

During the `$ python manage.py generate_aes_keys` command:

Wrote new key: foo.key
Not overwriting file: foo.key
Not overwriting file: foo.key
Not overwriting file: foo.key
Not overwriting file: foo.key
Not overwriting file: foo.key
Error: At least one key file already exists, not overriding.
The solitude has already been created at this step during the `generate_aes_keys` command
The /services/ url no longer exists

Not sure of the most pertinent one to test the service, the
/services/status/ response is concise enough but maybe useless?