Support multiple refund-message-delivery-cost-at-target-chain signed extensions

[svyatonik]

#1657 introduces new signed extension for refunding message relayers at the target chain (RefundRelayerForMessagesFromParachain). The issue is that it may only work with single bridge (single set of pallet_bridge_grandpa::Pallet + pallet_bridge_parachains::Pallet + pallet_bridge_messages::Pallet). We need to fix it to support multiple on-chain bridges.

It may be done using approach similar to what @serban300 has done with our other extensions (

parity-bridges-common/bin/runtime-common/src/lib.rs

Line 79 in 8b50630

macro_rules! generate_bridge_reject_obsolete_headers_and_messages {

).

[serban300]

Resolved via #1895