Add qnvim as a plugin

I provided a QtCreator plugin to use neovim as an editor server for QtCreator. This is the plugin's repo: https://github.com/sassanh/qnvim I've been using it for months and it's working alright. So I'm writing here to suggest embedding it in QtCreator as a plugin.

The benefits over FakeVim are enormous as it's using an actual neovim instance. So all the plugins the user installed on his vim, all his custom mappings, autocommands, etc whatever in his `init.vim` will work on his QtCreator too (except a few that need features of vim currently not supported by qnvim due to WIP state of some api of neovim.)

I guess it'll be beneficial for vim users who are used to their vim plugins (such as vim-surround) and want to code with Qt.