Augment gateway metrics collected

[vasco-santos]

@alanshaw added a few suggestions

📊 💡 Additional metrics to collect from the NFT gateway

• Histogram of file sizes (tracked in Limit gateway cache size and keep track of file size distribution nft.storage#1181)
  (MB) <0.5 | <1 | <2 | <5 | <25 | <50 | <100 | <500 | <1,000 | <5,000 ...
  ...all the way up to >32,000
• Requests per IPLD codec
• Requests by multihash hashing function
• Histogram of requests by file type:
  • image
  • video
  • text
  • html
  • script
  • directory
  • other (we should log these so we can add buckets over time)
• Direct CID requests vs CID+path
• Cache hits vs misses
• IPFS vs IPNS requests...also prerequisite IPNS support!? 😆