* [DOCS] Add custom URL instructions
* [DOCS] Update custom URL examples
* [DOCS] Add example for custom URL
* [DOCS] Add ML category terms custom URL example
* [DOCS] Add tip for pop-up ML custom URLs
* [DOCS] Address feedback about ML custom URLs
* [DOCS] Clarify impact of interval on custom URL
Original commit: elastic/x-pack-elasticsearch@eee192226f
Lisa Cawley