Add type hints to media rest resources. (#9093)

changelog.d/9093.misc

synapse/rest/media/v1/_base.py

synapse/rest/media/v1/config_resource.py

synapse/rest/media/v1/download_resource.py

synapse/rest/media/v1/filepath.py

synapse/rest/media/v1/media_repository.py

synapse/rest/media/v1/media_storage.py

synapse/rest/media/v1/preview_url_resource.py

synapse/rest/media/v1/storage_provider.py

synapse/rest/media/v1/thumbnail_resource.py

synapse/rest/media/v1/thumbnailer.py

synapse/rest/media/v1/upload_resource.py

synapse/storage/databases/main/media_repository.py