vimPlugins: Automatic rename deprecations

When an updated redirect results in a package name change, not just an
owner change, throw an error to warn users the package names has
changed.

pkgs/misc/vim-plugins/deprecated.json

@@ -0,0 +1,6 @@
+{
+    "gist-vim": "vim-gist",
+    "vim-jade": "vim-pug",
+    "vundle": "Vundle.vim",
+    "youcompleteme": "YouCompleteMe"
+}