Replaces all usages of `StreamIdGenerator` with `MultiWriterIdGenerator` (#17229)

changelog.d/17229.misc

synapse/_scripts/synapse_port_db.py

synapse/storage/databases/main/devices.py

synapse/storage/databases/main/end_to_end_keys.py

synapse/storage/databases/main/push_rule.py

synapse/storage/databases/main/pusher.py

...se/storage/schema/main/delta/85/02_add_instance_names.sql

...torage/schema/main/delta/85/03_new_sequences.sql.postgres

synapse/storage/util/id_generators.py

tests/storage/test_id_generators.py