[MAINTENANCE] stalebot configuration (#5301)
[MAINTENANCE] stalebot configuration (#5301)

StaleBot configuration.
* Moved to new cfg format
* disabled for PR's
  * only runs on Issues for time being
* Set to stale after 30 and close after 7 on issues only
  * date of init 2022-06-23T00 and future.
great-expectations/great_expectations,great-expectations/great_expectations,great-expectations/great_expectations,great-expectations/great_expectations