bug: hyper storage returns stream of "Not found" JSON when object is not found

[TillaTheHun0]

Currently, if an object in a storage service is fetched, but is not found, hyper storage will respond with a ReadableStream of nothing. This is difficult for the consumers to handle in their code.

If the object is not found, then hyper storage should respond with a 404 and JSON following a "hyper error response" shape:

{
  ok: false,
  status: 404
}