Added resource component documentation (WIP)

WIP documentation for the proposed resource component.

The component is here: https://github.com/dantleech/Resource

Its still not 100% finished and its scope isn't completely finalized, but some documentation should help to explain its purpose at least :)

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | yes
| Applies to    | all
| Fixed tickets | ---