feat: show `ipfs://` iframe

[olizilla]

• see if ipfs:// urls are supported by setting one as the src of an iframe.
• add service worker to handle the redirect from ?uri=%s
  • otherwise you need a local server to do the same redirect as dweb would do.
  • service worker seems more portable, and could let the user set their own gateway

License: MIT Signed-off-by: Oli Evans [email protected]