Refactor renovate testing from snippet to renovate repository
This MR moves @lucus.li Renovate testing scripts to a more permanent location, with more documentation. As the example renovate.json is quite ad-hoc, I've simply included it in-line with the instructions.
The testing script also needs to be refactored for user-friendliness and correctness.
More context for this MR can be found here
Edited by Alec Xu