feat: Implement pipeline-wide policy config

[scarmuega]

This PR introduces a new way to define pipeline-wide runtime policies to handle known errors.

The policy is configured by adding a top-level section in the toml such as this:

[policy]
missing_data = "Skip" | "Warn" | "Default"
cbor_errors = "Skip" | "Warn" | "Default"
ledger_errors = "Skip" | "Warn" | "Default"
any_error = "Skip" | "Warn" | "Default"