Fetch go-ipfs from GH instead of ipfs.io

[expede]

Closes #537

Changelog

• Grab go-ipfs from GitHub instead of ipfs.io
  • Remove "bootstrap" environment, since no longer fetched from an IPFS gateway
  • Have to unzip & untar it, since that's how they provide it
  • Comparable download performance to ipfs.io (surprising!), but it... you know... will always work
• Better interface for grabbing a specific go-ipfs build
  • Extensible to more architectures (e.g. native M1), but leaving for now
• Switch from IPFS 0.7 -> 0.9
  • Still takes "a while" for the daemon to start 😭
  • Push seems roughly the same speed 👍
• Drop special-cased Nix environment (Linux works these days)
• Bump Stackage to 18.1

Visual Evidence

[expede]

@walkah that's a good point. I'll extract that GH stuff out 👍