Unify v1 and v2 REST client APIs (#5226)

changelog.d/5226.misc

scripts-dev/list_url_patterns.py

synapse/app/frontend_proxy.py

synapse/rest/client/v1/base.py

synapse/rest/client/v1/directory.py

synapse/rest/client/v1/events.py

synapse/rest/client/v1/initial_sync.py

synapse/rest/client/v1/login.py

synapse/rest/client/v1/logout.py

synapse/rest/client/v1/presence.py

synapse/rest/client/v1/profile.py

synapse/rest/client/v1/push_rule.py

synapse/rest/client/v1/pusher.py

synapse/rest/client/v1/room.py

synapse/rest/client/v1/voip.py

synapse/rest/client/v2_alpha/_base.py

synapse/rest/client/v2_alpha/account.py

synapse/rest/client/v2_alpha/account_data.py

synapse/rest/client/v2_alpha/account_validity.py

synapse/rest/client/v2_alpha/auth.py