Remove window.ipfs

[dongle-the-gadget]

Problem

IPFS Companion 2.11 and newer no longer exposes window.ipfs, resulting in the download page erroneously saying "No local IPFS client has been detected."

Solution

Provide a single link to the Cloudflare IPFS mirror instead of trying to create a link to the user's mirror. If the user has the companion extension enabled and functioning, the companion will automatically redirect the Cloudflare mirror to the user's own mirror.