Add a primitive helper script for listing worker endpoints. (#15243)

changelog.d/15243.feature

synapse/_scripts/generate_workers_map.py

synapse/federation/transport/server/__init__.py

synapse/federation/transport/server/federation.py

synapse/rest/client/_base.py

synapse/rest/client/account.py

synapse/rest/client/account_data.py

synapse/rest/client/devices.py

synapse/rest/client/events.py

synapse/rest/client/filter.py

synapse/rest/client/initial_sync.py

synapse/rest/client/keys.py

synapse/rest/client/knock.py

synapse/rest/client/login.py

synapse/rest/client/presence.py

synapse/rest/client/profile.py

synapse/rest/client/push_rule.py

synapse/rest/client/read_marker.py

synapse/rest/client/receipts.py

synapse/rest/client/register.py