*: mv {,nixos}-configuration, restructure vim pkgs

pkg-configuration/vim-derivates/neovim.nix

@@ -0,0 +1,33 @@
+{ pkgs
+, additionalRC ? ""
+, additionalPlugins ? []
+, ... }:
+
+pkgs.neovim.override {
+  vimAlias = true;
+  configure = {
+    # add custom .vimrc lines like this:
+    customRC = (import ./commonrc.nix {}) + ''
+      " deoplete {
+      let g:deoplete#enable_at_startup = 1
+      let g:deoplete#enable_smart_case = 1
+      " }
+    '' + additionalRC;
+
+    vam.knownPlugins = pkgs.vimPlugins; # optional
+    vam.pluginDictionaries = [ # full ducomentation at github.com/MarcWeber/vim-addon-manager
+      "vim-addon-vim2nix"
+      "vim-airline"
+      "vim-addon-nix"
+      "ctrlp"
+      "vim-css-color"
+      "rainbow_parentheses"
+      "vim-colorschemes"
+      "vim-colorstepper"
+      "vim-signify"
+      "deoplete-nvim"
+    ] ++ additionalPlugins;
+  };
+  extraPythonPackages = [];
+  withPython3 = true;
+}