Drop txpool v1 (#3017)

cmd/integration/commands/reset_state.go

cmd/integration/commands/stages.go

cmd/integration/commands/state_stages.go

cmd/rpcdaemon/cli/config.go

cmd/rpcdaemon/rpcdaemontest/test_util.go

cmd/utils/flags.go

core/blockchain.go

core/tx_journal.go

core/tx_list.go

core/tx_list_test.go

core/tx_noncer.go

core/tx_pool.go

core/tx_pool_test.go

eth/backend.go

eth/protocols/eth/handler.go

eth/protocols/eth/handler_test.go

eth/protocols/eth/protocol.go

eth/stagedsync/default_stages.go

eth/stagedsync/stage_mining_create_block.go

eth/stagedsync/stage_txpool.go