Manually generate the default config yaml, remove most of the commandline arguments for synapse anticipating that people will use the yaml instead. Simpify implementing config options by not requiring the classes to hit the super class

synapse/server.py

@@ -59,7 +59,6 @@ class BaseHomeServer(object):
         'config',
         'clock',
         'http_client',
-        'db_name',
         'db_pool',
         'persistence_service',
         'replication_layer',