Move parameters out of the …_message components

This commit refactors the `email_message` and `sms_message` UI components to
take fewer parameters.

`name`, `edit_link` and anything to do with versions are identical for both
text and email messages so I’ve moved them to the pages where you choose a
template or see the versions.

This commit also tidies up the wording and styling of the template history
stuff.

app/assets/stylesheets/main.scss

@@ -51,6 +51,7 @@ $path: '/static/images/';
 @import 'components/pill';
 @import 'components/secondary-button';
 @import 'components/show-more';
+@import 'components/message';
 
 @import 'views/job';
 @import 'views/edit-template';