Custom Colors/Theme Config

**Is your feature request related to a problem? Please describe.**
This is potentially linked to any color related requests

**Describe the solution you'd like**
I believe a good solution to this would be to allow the use of Hex Color Codes in config to set colors as well as the ability to color each UI feature.

**Describe alternatives you've considered**
A good alternative to this would be to allow setting color aliases in the config or a sourced file

**Additional context**
Lazygit implemented a similar feature for setting colors/themes.