Split Resources into Chunks for Storing

[s-rah]

Currently we drop resources larger than 2MB because of limitations with the database - regardless of which backing store we end up with in the future, we are likely always going to need to chunk blobs.

We should

• Configure a max object size for downloaded resources (set probably around 10MB for default)

• Split resources smaller than this into <1MB chunks and store them in the DB in a way that can be put back together later e.g.

    resource:{
   url net.URL
   data []byte
   nextChunk int //id to resource chunk containing next part of the data
   }