Add "White" as a cable color

[DanSheps]

Environment

• Python version: 3.6
• NetBox version: 2.5.1

Proposed Functionality

Add color white to the cable colors.

Optionally add:

• slate(Dark Grey works, almost identical color)
• rose
• violet (Fuschia works, almost identical color)
• aqua

Use Case

These fiber strand colors are missing

Database Changes

None

External Dependencies

None

[jeremystretch]

I'm fine with adding white. Any additional colors will need to be compared to the existing list to ensure they are easily distinguished from all existing colors.

We'll also need to ensure that the proper foreground color is used. There's a utility function named foreground_color() which outputs the ideal foreground color (black or white) given an arbitrary background color. We can expose this as a template filter.