Remove SOURCE_PARACHAIN_PARA_ID (#1716)
* Remove SOURCE_PARACHAIN_PARA_ID Remove SubstrateParachainsPipeline::SOURCE_PARACHAIN_PARA_ID * Avoid duplicate ChainBase and ParachainBase implementations * Replace ChainShadow with UnderlyingChainProvider
* Remove SOURCE_PARACHAIN_PARA_ID Remove SubstrateParachainsPipeline::SOURCE_PARACHAIN_PARA_ID * Avoid duplicate ChainBase and ParachainBase implementations * Replace ChainShadow with UnderlyingChainProvider