Add base16 framework support

[mr-cheffy]

What feature would you like to see?

Adding native support for base16 automatically provides a access to a huge amount of color schemes without having to reinvent the wheel.

This could be done either by providing a config file that can be overridden (thus enabling easy system wide pallette switching through flavours for example) or by integrating the schemes it into the theme store (for convenience) or both.

Other details

No response

~ Created automatically from issue: #641