feat: improved block submission error handling

[tzdybal]

• more detailed application level error information
• exponential backoff for block submission
  • simple "times 2" strategy with upper limit
  • max backoff timeout is equal to block time
  • increased number of retries to 30

Resolves #423
Resolves #426

[tzdybal]

Resilient like a honey-badger 🍯 🦡

[Wondertan]

Edit: just saw another issue confirming this.

Code 19 in SDK means tx is already included in the mempool, right?

[tzdybal]

Right: https://github.com/cosmos/cosmos-sdk/blob/89323385043cd39283a57644e7c59c4ee4b90492/types/errors/errors.go#L76