Add legend about bands/range with color picker

[markov00]

Is your feature request related to a problem? Please describe.
related to TSVB/Visualize gauge replacement

Describe the solution you'd like
When displaying a bullet graph, the legend can be shown to display the various ranges values/color, allowing color picking.

Describe alternatives you've considered
to discuss:

• the bullet graph already shows a range of colors and their respective values, it looks redundant
• do we really need the color picking consistent and used only from the legend?

Additional context
related to TSVB/Visualize gauge replacement

[ghudgins]

do we want legends on goal visualization? does it benefit with the new accessible values? could we wait for a shared legend feature and close this issue?

[rshen91]

Linking over #1218 (comment) and #1218 (comment)

[nickofthyme]

@gvnmagni Do you think we should close this issue or do you see value in adding a legend to the new bullet design?

[gvnmagni]

The only useful way I can of this is when we have color ranges that stand for something, as we can see in the attached images (a quick mockup), I think this is an edge case but I wouldn't drop completely the concept, I would like to be sure about this use first

[markov00]

let's close this until we don't have a formal request for that