Move move .emacs.d out of configs/shared

Moving all of my Emacs-related files into their own directory at the root of
this repository.

emacs/.emacs.d/snippets/c-mode/struct

@@ -0,0 +1,7 @@
+# -*- mode: snippet -*-
+# name: struct
+# key: struct
+# --
+typedef struct $1 {
+  $2
+} $1_t;