Mobile Packet Verifier Transaction Recovery

[michaeldjeffrey]

This PR is step 1 in getting back to using helium-lib for solana.
It does not currently use helium-lib for anything, yet.
But adds failure resilience for mobie-packet-verifier.

All the changes in iot-packet-verifier were aimed towards making the integration tests use more production code.
The only new change here, is we check if there are any in flight transactions before burning.
There should only ever be 1 for this iteration of the code.

Mobile Packet Verifier

• Can handle a shutdown with an inflight transaction.
• Pending Transactions are handled with 2 new db tables.
  • pending_txns and pending_data_transfer_sessions.
  • "burns" and their sessions are moved to the new tables when submitted.
    • If the transaction succeeds, the sessions are written to s3 and the pending txn is removed.
    • If it fails, the pending txn is deleted, and the sessions are moved back to the main data transfer table.
  • Burn values are derived from sessions in data_transfer_sessions.
• We always confirm any pending transactions before burning
• There should only ever be a single pending transaction

IoT Packet Verifier

• Updated tests to use #[sqlx::test] to use production code.
• Removed unused Mock structs.
• Make sure we only have 1 in flight transaction at a time.

Solana

• TestSolanaClientMap replaces Arc<Mutex<HashMap<PublicKeyBinary, u64>>> impls