Add the ability to include different parts of the config from external sources.

First pass idea for this:

• Allow substituting core components with a wiki: or url: string that points to raw text
  • Run, Check, Rule, Action
  • Think it would be less complex to allow only single objects to be fetched, rather than an array of them?
    • Don't want to have to deal with merging things
• On config parsing each fetch would be cached with the validated object and replaced if found anywhere else in config
• Expand config editor validity schema to validate individual components

Potential problems:

• Duplicate objects, how to address?
• Cache time and behavior for checking
  • Not a problem for external url: but if many wiki: used could consume lots of api calls. Is there a way to batch? Or allow cache busting on wiki: string?