gnu: Have vim packages use vim-build-system.

* gnu/packages/vim.scm (vim-neocomplete, vim-neocomplete-snippets,
vim-neosnippet, vim-scheme, vim-luna, vim-fugitive, vim-airline,
vim-airline-themes, vim-syntastic, neovim-syntastic, vim-solarized,
vim-rainbow, editorconfig-vim, neovim-packer, vim-guix-vim,
vim-asyncrun, vim-dispatch, vim-gemini-vim, vim-eunuch, vim-slime,
vim-vlime, vim-paredit, vim-surround, vim-gnupg, vim-ctrlp,
vim-mucomplete, vim-gitgutter, vim-characterize, vim-tagbar,
vim-nerdtree, vim-nerdcommander):
[build-system]: Switch to vim-build-system.
[arguments]: Adjust accordingly.
* gnu/packages/code.scm (global)[arguments]: Move vim files to their new
location.
* gnu/packages/lisp.scm (txr),
* gnu/packages/mail.scm (msmtp),
* gnu/packages/rust-apps.scm (skim),
* gnu/packages/vim.scm (vifm),
* gnu/packages/wm.scm (fluxbox): Same.

Co-authored-by: Efraim Flashner <efraim@flashner.co.il>
Signed-off-by: Efraim Flashner <efraim@flashner.co.il>
Change-Id: I8b3e5d65d76a100c3dbddc1ae562b72966c2b304

gnu/packages/code.scm

@@ -237,8 +237,9 @@ highlighting your own code that seemed comprehensible when you wrote it.")
                  (lambda _
                    ;; Install the plugin files in the right place.
                    (let* ((data (string-append #$output "/share/gtags"))
-                          (vim  (string-append #$output
-                                               "/share/vim/vimfiles/plugin"))
+                          (vim  (string-append
+                                  #$output
+                                  "/share/vim/vimfiles/pack/guix/start/global/plugin"))
                           (lisp (string-append #$output "/share/emacs/site-lisp/"
                                                #$(package-name this-package) "-"
                                                #$(package-version this-package))))