Merge pull request #3534 from krombel/use_parse_and_asserts_from_servlet

changelog.d/3534.misc

synapse/federation/federation_base.py

synapse/http/servlet.py

synapse/rest/client/v1/admin.py

synapse/rest/client/v1/directory.py

synapse/rest/client/v1/initial_sync.py

synapse/rest/client/v1/push_rule.py

synapse/rest/client/v1/pusher.py

synapse/rest/client/v1/register.py

synapse/rest/client/v1/room.py

synapse/rest/client/v2_alpha/account.py

synapse/rest/client/v2_alpha/devices.py

synapse/rest/client/v2_alpha/register.py

synapse/rest/client/v2_alpha/report_event.py

synapse/rest/media/v1/identicon_resource.py

synapse/rest/media/v1/preview_url_resource.py

synapse/rest/media/v1/upload_resource.py

synapse/streams/config.py