Also adds some missing youtube links to legacy potd.json file

Add some images and check 'generic_news' to see it in latest news

Also fix bug with SiteSettings Admin

Also adds tests for htmleditor forms.
Fixes a bug where a banner wouldn't go to a hardcoded view

Also sets the sources for news articles to use the filter widget

Banner html is now in banner_tag.html
The html has the first banner set, so that if javascript is disabled a banner
is still visible and clickable.

The title/description for a generic banner is set as the document name, but
the coded views are hardcoded with 'title': 'Title of Page'. So these will
not easily be changeable by site admins. I could also just not show generic
views for them. (If a title is not given, or 'show_generic' is not given as
True, then no generic banner is shown.)

This adds a volunteer_node to SiteSettings.
This adds a VIEW_LOGIN to NavigationNodes.

Information on what to do with that data is at the bottom of the base.html
template

Requires a reset of usta and htmleditor (Easiest to delete db and start over)