Port of onedark to Fennel, so that we generate fast Lua code.

Work in Progress

I have been daily driving this for a few years, but there may still be bugs. A number of plugins are not supported (mostly because I don’t use them). At some point, I would like to provide easier personnalisation, but it’s not quite there yet. If you want to customize this colorscheme, you will have to change the Fennel code and recompile it.

A few highlight group might still refer to NVim default colorscheme. They can be found by running :highlight and then searching the output for Nvim.