Restyling of textarea input fields

This mostly includes the Code Mirror instances as well as textarea fields on the credentials form. Also includes the styling of radio button for the variables textarea box.

awx/ui/client/src/forms/Credentials.js

@@ -20,7 +20,7 @@ export default
             forceListeners: true,
 
             actions: {
-                
+
             },
 
             fields: {
@@ -263,11 +263,11 @@ export default
                         variable: 'key_required',
                         init: true
                     },
+                    class: 'Form-textArea',
                     hintText: "{{ key_hint }}",
                     addRequired: false,
                     editRequired: false,
                     awDropFile: true,
-                    'class': 'ssh-key-field',
                     rows: 10,
                     awPopOver: "SSH key description",
                     awPopOverWatch:   "key_description",