* Add coc lua extension to allow us to install plugins during NukeVim
install
* Update docs to reflect that coc extension installation makes the
install process look broken.
* Migrate one of the holdover autocmds from vimscript to lua extension
so it doesn't cause errors when coc is disabled
This solves first time startup in that the plugins are available when
other modules would normally expect them to be, instead of having to
handle a special case of them only being available later.
Adam Pippin