Add security note about AngularJS in Smarty
Created by: seancolsen
I think this PR is pretty straightforward. Will merge in 5 days if no one provides feedback.
@seamuslee001 you might be interested in this. I was thinking that potentially we could have an "AngularJS" section within your security page, perhaps just with this content in it. If you think that's a good idea, then we could move this content over when you make your page, and link to it from where I've added it now.