Tidy up helper somewhat, and start on implementing reprocess

Tidy up helper somewhat, and start on implementing reprocess

For helper:
 * Helper does most of the json I/O so we don't need to import in other files
 * Add some structs to manage the complexity of multiple routing keys
 * Various convenience options (IncludeDate on send, Source in the RabbitConfig) for easier scope

For reprocess:
 * Reads in temp pretty simply, and sets prometheus gauges as we've done before
 * Kinda handles DIY temperature (resends and prometheus gauge), and does not care about motion (so won't send it back out)
 * Weird chain of structs to implement different devices
 * Have not started on power or other complicated logic yet