Align Rococo/Wococo/Polkadot/Kusama bridge hub weights with the ones defined in cumulus

[serban300]

Resulted from #1672

While adding integrity tests for Rococo -> Wococo and Wococo -> Rococo we stumbled upon the following issue:

For BridgeHubRococo and BridgeHubWococo we expect to find the weights defined in polkadot-core which use the constants defined also in polkadot-core. But instead the runtime uses the same formula, but with other constants defined in cumulus/parachains/common and other BlockExecutionWeight.

We need to use the same weights in the bridge hubs definitions in cumulus and in the relayer definitions.