Friendlier cached GET API

[mildbyte]

If the GET API receives an unhashed SQL query in the URL (e.g. just urlencoded), hash it and redirect the user to the hashed endpoint), as per https://github.com/splitgraph/seafowl/issues/20#issuecomment-1204130690

Need to consider the fact that the redirect will only make sense if the client ends up sending the actual query in the GET body/header correctly. So we need to use a redirect that preserves the headers/body and the client needs to send the headers/body in the original request as well, potentially limiting the friendliness of this.