useFetchHelpText custom hook

[dpgraham4401]

Add a custom hook for fetching help text for a given node.

This hook should return an object with the following properties

{
  data:  HelpTextData
  isLoading: Boolean
  error: HelpTextError
}

The interfaces for data and error will need to be defined as well (they don't need to be named the above).

as a prop, the hook should accept the name of a config, which will correspond to a file name.

We may want to statically type the help text prop to an enum, however that would require ajusting the enum every time the help text configs are renamed or new ones are added.