Enable tweet embedding

[dmarx]

• https://dev.twitter.com/web/embedded-tweets
• https://github.com/eriktaubeneck/flask-twitter-oembedder

Lowest LOE: embedding "media" tweets since we essentially have the status id already. Higher LOE: embedding "url" tweets.

[dmarx]

Scavenging code from this guy's TweetRenderer class looks like a potentially good option: https://github.com/thusoy/blag/blob/851b0aa8538d9e15e6759d96f1a6fc40266c81e6/blag/blocks.py#l146

Also, there's some good JS links at the bottom of this page: https://dev.twitter.com/web/embedded-tweets