Refactor Color/True Color - Make TrueColor default

[tig]

• The TrueColor support in v2_develop works only for Windows Terminal (see Add TrueColor support to CursesDriver #2798 and Add TrueColor support to NetDriver #2799).
• Attribute, Color, etc... all need to be refactored to make this work generically so the other drivers can work too.
• TrueColor should be the default; fallback to 16 color mode would be automatic if possible. If not, users should be able to force it via ConfigurationManager. E.g. "Application.Force16ColorMode" : true.
• Persistence of colors to ConfigurationManager needs to be sorted out.

[tig]

Woot!