[XCMv5]Remove XCM testnet NetworkIds (#5390)
# Context Close #5241, for more detail, please refer to [RFC0108](https://github.com/polkadot-fellows/RFCs/pull/108) # Changes - Remove `Rococo` and `Westend` from `NetworkId` * Add `Rococo Genesis Hash` and `Westend Genesis Hash` --------- Co-authored-by: Nazar Mokrynskyi <[email protected]> Co-authored-by: Bastian Köcher <[email protected]> Co-authored-by: Shawn Tabrizi <[email protected]> Co-authored-by: Adrian Catangiu <[email protected]> Co-authored-by: Francisco Aguirre <[email protected]>