[PBI] Standardize error handling

[devkelley]

Description

Current error handling is mostly consistent, but things like max-retries and consistent error messages are missing. This task is to standardize across the codebase.

Acceptance criteria

• Common retry method added for gRPC client calls, etc.
• Common error handling implemented across main service.
• Eliminate unwrap() statements except for cases where the variable has already been checked.
• Determine strategy for gracefully handling shutdown of the service.
• Ensure logging statements are consistent across project