Add optional keys to groupedOutputs.data.*.stats.* to allow for better filtering support.

[connor-makowski]

These should include:

allowFiltering: To allow a filter to be applied to this state
allowCharting: To allow a stat to be selected in the chart dropdown
help: To have a little help button next to this stat for user reference

The idea is that some stats might be used for filtering, but not charting and vice versa. In general, both allow values should default to true and the help should not show if it is null or blank.

[luisvasq]

We have a filterable prop (added by Willem) for map filter items. Maybe we can rename allowCharting or simply stick with its name and rename filterable to allowFiltering.

[connor-makowski]

Are these in 2.1? If so we are stuck with them until 3.0

[luisvasq]

For now, it's only in cave_static because the default value of filterable is true, and it hasn't been added in any cave_app example yet. I think it's safe to rename it or change anything about it.