Use new upload pipeline in synapse import

cmd/export_synapse_for_import/main.go

cmd/import_synapse/main.go

cmd/s3_consistency_check/main.go

common/config/access.go

homeserver_interop/synapse/db.go

homeserver_interop/synapse/local_media.go

pipelines/pipeline_upload/pipeline.go

util/ids/snowflake.go