relayer metrics

[oclaw]

This PR adds metrics needed for monitoring state of the nil relayer service components

Added the following metrics:

• Common DB metrics (collection size, inserts, deletes)
• Event listener metrics (fetcher status, amount of incoming events, errors)
• Finality ensurer metrics (lag of updating finalized block value, amount of finalized & orphaned events)
• Transaction sender (relay/error count)

[notion-workspace]

Relayer metrics