Separating vim's config from neovim's config simplifies the deployment
of lua for neovim's configuration. At the same time, clean up current
neovim config by removing all outdated options and options with equal or
even better defaults. Furthermore, the 'old' vim configuration should be
kept as-is to ensure compability with older systems if needed.
As of now the link function follows the destination path if already
existent and then creates a new symlink in there. In order to not create
this unnecessary additional symlink a check has been added which simply
checks if a symlink already exists in order to delete it.
