Possibility to use comparators in Action Table

[pgrill79]

It would be great if you can use different operators for filtering in the action table. E.g. if there is a number or a date column, to give the possiblity to filter every thing > or < than the number or date.

[aeberhart]

This fits into a larger complex of "Business Intelligence" like functions. At the moment, we only support equality in the underlying all(db, table, filters) call where filter is a map of field=value.

see https://marmelab.com/react-admin/FilterList.html

[aeberhart]

we can maybe re-use the query editor logic