Update AppData Fetching

[bh2smith]

The backend is going to start encoding app data differently and we will need to change the inverse mapping

appHash --> CID

@vkgnosis shared the rust code that already does this here

and it appears we will just have to change the prefix here.

However we will need to continue to support the old style (forever) because old app hashes will always exist. Unless they plan to migrate all the old files to the new schema.

In terms of support there will be a block number for which the new content starts but is mixed (deployed in staging) with old and another block where we only support new app hashes. The code will need to know these blocks say (left, right) so that we use old on blocks below left, both on block between left and right and new on blocks after right. Might actually be easier to just check both always (with priority on the new schema).