Add opening and closing logo/title screens

[tim1mw]

Generate an image with the PyCon logo and presentation title to use as a 3-5 second opening banner.

The end image will be a static "The end" image with the PyCon logo.

Ideally, these images will fade in, but that may need a full re-encode of the recording which defeats purpose of the encoding for fast cuts. So this will need some thought and is a "nice to have"

[IanTaylorFB]

I saw something in the YouTube docs about a sort of 'end credit' thing. We may be able to do this by uploading a static image / clip, and letting YouTube do the lifting. Not sure about the start - we may still have to do that for each session.

[tim1mw]

If we can do it with something in the YouTube channel settings, that's worth checking out!