[Lens] Allowed fixed interval in a number histogram

[wylieconlon]

The automatic number histogram in Lens is not precise, and there are advanced users who would benefit from the ability to define the interval numerically. This mostly happens if the data fits into a known range, such as in this discuss question.

This feature request would basically create 3 modes for the Intervals function in Lens.

[elasticmachine]

Pinging @elastic/kibana-app (Team:KibanaApp)

[wylieconlon]

This feature would also allow the number histogram to work with range data types.

[wylieconlon]

Another thing to consider here: rollups are done on a fixed histogram interval as well. We probably need a mode that's for both rollups and number histograms where it's fixed interval only, not as a 3rd mode.

[timductive]

Closing for now as we don't have user requests for this.