Add videos to archive page

[iancrowther]

We have a rich archive of videos on youtube and vimeo.

Each months videos should live in a playlist which can be accessed via the youtube api

The vimeo videos could be ported to youtube to be consistant.

see:
https://github.com/lnug/feedback/issues/80
https://github.com/lnug/feedback/issues/82

[julienbrunuk]

See PR #88

[iancrowther]

+1