feat: add ansi colours

[backwardspy]

demo of what works currently:

---
whiskers:
  version: '2.5'
  hex_format: "#{{R}}{{G}}{{B}}"
---
{% for id, c in flavor.ansi_colors -%}
{{ c.name }} ({{ c.code }}) {{ c.hex }}
{% endfor -%}

Black (0) #5C5F77
Red (1) #D20F39
Green (2) #40A02B
Yellow (3) #DF8E1D
Blue (4) #1E66F5
Magenta (5) #EA76CB
Cyan (6) #179299
White (7) #ACB0BE
Bright Black (8) #6C6F85
Bright Red (9) #DE293E
Bright Green (10) #49AF3D
Bright Yellow (11) #EEA02D
Bright Blue (12) #456EFF
Bright Magenta (13) #FE85D8
Bright Cyan (14) #2D9FA8
Bright White (15) #BCC0CC

todo:

• ansi pairs
• overrides
• docs
• test on actual terminal ports
  • then publish stable ctp/rust crate