Domain chain network stack updates

[shamil-gadelshin]

This PR prepares the domain networking stack for domain snap-sync.

Changes:

• new custom request-response protocol for confirmed domain block receipts. We need this protocol to acquire the correct domain block for snap-sync.
• restore state and block requests protocol for domains. We'll get the required state and block from the domain network using restored protocols.
• disable domain sync by setting pause_sync variable to true on domain network initialization. We don't rely on Substrate sync in domain network.
• DomainsApi modification (confirmed domain block receipts) - for exporting the last confirmed domain block from the runtime state and returning it using a new custom protocol.

Code contributor checklist:

• [x] I have read, understood and followed contributing guide