Embedded videos need metadata

[mbakeryo]

The title should be there (hidden) before a user
gets to the video player.

[conorom]

@jmcglone Here is a nice summary of this kind of thing:
https://dequeuniversity.com/tips/provide-iframe-titles

Can you confirm that:

1. the <title> of the embedded page is what we're targeting here, so for now I'm just going to set that to the FileSet title
2. the iframe itself should have a title attribute as well

[conorom]

Will create a PR following the advice in that link.