Support Ad-Hoc Filters as Business Variable

[sig-piskule]

It would be very useful to be able to show each Filter Label, and each associated Filter Value, all as a tree.

For example:

namespace: a
namespace: b
namespace: c
pod: 1
pod: 2
pod: 3

The output from the Business variable would be

> namespace
[ ] a
[ ] b
[ ] c
> pod:
[ ] a
[ ] b
[ ] c

This would make filtering logs in Loki dramatically easier, since the U.I. being stuck at the top of the screen is less than desirable.