What is a interplanetary provider of HTTP content?

(Choose as many as make sense, but we will need to allocate codecs for the ones we do want)

1. Directory:
   Multiaddr syntax:/dns/site.com/tcp/80/http/httpath/ {b64:path}
   Semantics: request site.com/path/cid
   (Used already in go-legs for network indexer ingest of ipld advertisements.)

   Caveats:
   as a provider grows large, the provider would naturally want to shard the directory. there may need to be another parameter for the multiaddr to support this.

2. Car:
   Multiaddr syntax: /dns/site.com/http/httpcar/{b64:path/to/file.car}
   Semantics:
   1. If carv2: read index, then read relevant block
   2. If carv1: scan through thing inefficiently until getting block?

   Questions:
   * Should Cars without an index be supported?
   * Is there a data structure within a car that could be used as an alternative? e.g. if the car begins with a root node that is a hamt with keys of contained CIDs and values of offset in the car where that CID is contained.