cmd, eth, les, mobile: make networkid uint64 everywhere

cmd/faucet/faucet.go

cmd/puppeth/wizard_genesis.go

cmd/utils/flags.go

eth/backend.go

eth/config.go

eth/gen_config.go

eth/handler.go

eth/helper_test.go

eth/peer.go

eth/protocol.go

eth/protocol_test.go

ethstats/ethstats.go

internal/ethapi/api.go

les/backend.go

les/handler.go

les/peer.go

mobile/geth.go