Color -> Tui

Parse hex colors to tui rgb colors

#c3f111 -> Color::Rgb(195,241,17)

Note that the indexed colors are NOT HEX
#142 -> Color::Indexed(142)

Example

```rust

[derive(Serialize, Deserialize, PartialEq)]

sruct ColorStruct { #[serde(with = "colortotui"] color: tui::style::Color, #[serde(with = "colortotui::optional"] optional_color: Option, }

let colortext = r###"{ "color" : "#12FC1C", "optionalcolor" : "#123" }"### let t: ColorStruct = serdejson::fromstr::(color_text).unwrap();

let c = ColorStruct { color: Color::Rgb(18, 252, 28), optional_color: Option

assert_eq!(t, c);

```