Report per request metrics for all of the things using request_handler

synapse/http/server.py

synapse/replication/pusher_resource.py

synapse/replication/resource.py

synapse/rest/key/v1/server_key_resource.py

synapse/rest/key/v2/remote_key_resource.py

synapse/rest/media/v1/download_resource.py

synapse/rest/media/v1/preview_url_resource.py

synapse/rest/media/v1/thumbnail_resource.py

synapse/rest/media/v1/upload_resource.py