Allow config file path to be configurable in in synctl
Allow config file path to be configurable in in synctl

Also, allow it to be run from directories other than the synapse directory

matrix-org/synapse,matrix-org/synapse,TribeMedia/synapse,matrix-org/synapse,TribeMedia/synapse,TribeMedia/synapse,matrix-org/synapse,iot-factory/synapse,iot-factory/synapse,TribeMedia/synapse,matrix-org/synapse,iot-factory/synapse,iot-factory/synapse,iot-factory/synapse,TribeMedia/synapse,matrix-org/synapse