contrib/systemd: log_config.yaml: do not disable existing loggers

It turned out that merely configuring the root logger is not enough for
"catch-all" semantics. The logging subsystem also needs to be told not
to disable existing loggers (so that their messages will get propagated
to handlers up the logging hierarchy, not just silently discarded).

Signed-off-by: Ivan Shapovalov <intelfx100@gmail.com>

Allow endpoint for verifying recaptcha to be configured

Use ultrajson when possible. Add option to turn off freezing of events.

Conflicts:
	synapse/handlers/auth.py

Make HTTP clients use connection pools.

Remove a deep copy

SYN-390: Don't modify the dictionary returned from the database here either