Example generic rust-based subsystem handler

[plauche]

• [x] Create example rust based handler
  • [x] Present GraphQL + GraphiQL endpoints
  • [x] Example subsystem model
  • [x] Handle query accessing subsystem
  • [x] Example functions for fetching subsystem data

[plauche]

Create generic example rust handler (graphql query)

[jacoffey3]

This is like Greek to me. I might want your help deciphering this at some point Ryan, otherwise it'll be useless for me to review.

[plauche]

@CatGarab currently you can query for power and uptime independently. The power() or uptime() functions will only be called when that attribute is queried.