[UI] Embed HUD in iframe

[davidkpiano]

• All of the HUD's UI components should be in an isolated <iframe>
  • Can also consider a shadow DOM a la web components (@legomushroom)
• Add small amount of "bridge" JS that communicates between the Glimpse.Browser.Agent and the HUD
  • Can use (postMessage())[https://developer.mozilla.org/en-US/docs/Web/API/Window/postMessage] to accomplish this

This will mitigate concerns related to:

• style isolation (there is no guarantee that HUD styles are not overridden by inherited styles)
• performance metrics: currently, the performance numbers (as well as load times, etc.) can be influenced by the HUD, since they are all within the same main thread.

[legomushroom]

I see a lot of benefits in doing this, wondering if we can go further and make a component that can be embedded anywhere?