Refactor code to use dependency injection

[curieos]

Multiple objects create their own dependencies, which causes tight coupling and makes testing more difficult. An example is the rest server:

Firmware/src/restserver.cpp

Lines 15 to 19 in 881d03b

	RestServer::RestServer(AsyncWebServer *server, Scheduler *scheduler) {
	this->scheduler = scheduler;
	module_service = new ModuleService();
	plant_service = new PlantService(scheduler);

This should be changed so the root file (main.cpp) or a dependency injection framework creates these and passes them in as references. Don't worry about the sensors in plant service for now, those will be fixed in #4.