improve deployed testnet resilience

[rafaelcr]

The chainhook deployment for primary testnet is having a few issues that have been difficult to debug and solve. This issue will keep track of all the different sub-tasks that need to be resolved before we can get that environment back on track:

• return 500 status codes properly when a Stacks block could not be ingested #646
• add a configurable max timeout for predicate requests #643
• Improve resilience for when chain state becomes outdated #630
• Investigate why the Chainhook chain segment can become outdated #623
• Validate highest Bitcoin block after Chainhook node restart #620

[smcclellan]

The remainder of this is moved to this ticket.