Embedding pens from CodePen

[Falco]

@Roman_Rizzi

On the other hand, we could possibly set a specific user-agent that can be allowed on your side?

I believe we set one per:

Onebox user agent

This commit adds a custom User-Agent to discourse oneboxes: https://github.com/discourse/discourse/commit/8bc93c0b018045bf23769b8ecc4ec5b493368667 The User agent looks like this: Discourse Forum Onebox v1.8.0.beta13