[FEATURE] Color customization

[guibranco]

Description

Enable color customization in the SVG via query string parameters.

Tech notes

Originally reported here: fredericojordan/progress-bar#8 by @malex5335

Screenshots or Diagrams

Additional information

Documentation:

https://progress-bar.dev/58/?title=colorful&progress_background=ffc0cb&progress_number_color=000