Improve Twitter integration

With the most recent example being #3864, our current Twitter-embedding solution of gatsby-remark-embedder+gatsby-plugin-twitter has some downsides:

• Builds break if a tweet is deleted or protected, and they persist unstyled in cache
• Loads a whole extra external JS embed bundle from Twitter
• Just looks kinda ugly

(it might just be me, but it really just dumps text like if you copy-pasted it while adding a couple links in. We’re downloading a library for this?)

As far as an alternative implementation, I can think of two main routes off the top of my head:

Use a custom component with pasted content

Pros:

• simplest implementation code-wise
• doesn’t break regardless of what happens to the tweet
• pretty easy to do overall
• Would need a custom component to add boilerplate that keeps us in line with Twitter’s Tweet display guidelines

Cons:

• doesn’t update if tweet changes, is updated, or deleted.
• Slightly more difficult on editors than other options

gatsby-source-twitter

Pros:

• can maintain the slightly easier workflow of pasting a link instead of pasting a tweet
• can be heavily customized
• (can be) fully static

Cons:

• a significant amount of dev work that could balloon depending on requirements

[shcheklein]

Closing for now, we can come back to it later.

[shcheklein]

I would go with deleting them for now for simplicity. Let’s not spend time on building our own stuff here.