Add simple download link to embedded frame for webinars

[planetf1]

When using mobile to view the webinar page (see ref issue), it is difficult to read the charts as they require a lot of scrolling around, and the link to download (which is seen within the frame on web) is not visible.

This is caused by a combination of screen size & the use of touch interaction.

I suggest we add an explicit download/simple link to the charts

The youTube video links work fine on mobile, presumably the widget works better on mobile

(Tested iPhone 13 pro).

Thanks @planetf1 . Please raise a separate issue for "On a related point, can we also add a simple download link to the iframe embed? It is very awkward to read on mobile. Even on web I find dealing with the double scrollbar quite tricky?"

Originally posted by @davidradl in https://github.com/odpi/egeria-docs/issues/280#issuecomment-1034787666