Deprecate forUploads in favour of forKinds

cmd/import_synapse/main.go

cmd/media_repo/main.go

common/config/config.go

common/media_kinds.go

config.sample.yaml

controllers/download_controller/download_resource_handler.go

...ollers/thumbnail_controller/thumbnail_resource_handler.go

controllers/upload_controller/upload_controller.go

storage/datastore/datastore.go