Events to add

[iMattPro]

Some new template event locations that would be nice:

1. After header navbar, using overall_header_page_body_before

2. After footer navbar, using overall_footer_copyright_prepend

Some new PHP events:

1. An simple event inside our admin_controller::main

I created a simple extension to extend a new ad location and noticed that we need a way for such a simple extension to load its language file so the name of the added location will be translated in our location list in the ad's settings.