Improve support request details import form

Summary:
Created as standard layout that can be used for both the import and export form

Standardized components used, so that we work towards a Design Framework that is consistent. Took inspiration from some existing plugins.

Also fixed weird sidebar transparency.

Reviewed By: passy

Differential Revision: D18504078

fbshipit-source-id: 7649abf7aa3eba8ba635337a41274bba93738e81

src/utils/icons.js

@@ -48,7 +48,7 @@ const ICONS = {
   desktop: [12],
   directions: [12],
   internet: [12],
-  mobile: [12, 32],
+  mobile: [12, 16, 32],
   posts: [20],
   profile: [12],
   rocket: [20],