Grey values out of range instead of hiding

[ShrimpCryptid]

Use Case

Requested by @jcass11 and @jessicasyu!
The requested feature is to indicate the existence of cells even if they're not currently being colored, giving them an alternate color instead of hiding them.

Acceptance Criteria

• Cells outside of the range should have an alternate color applied to them instead of color ramp values.
• Add some UI element to turn on/off this feature.

Details

[toloudis]

end goal is that values out of range can be either hidden OR use an assigned color.

[ShrimpCryptid]

Options:

1. Hide values
2. Use custom color (grey by default)
3. Use color ramp

Use antd's color picker for the custom color option: https://ant.design/components/color-picker