rpc, evm: refactor (#588)

* stargate: refactor

* remove evm CLI

* rpc: refactor

* more fixes

* fixes fixes fixes

* changelog

* refactor according to namespaces

* fix

* lint

* remove export logic

* fix rpc test

* godoc

rpc/namespaces/net/api.go

@@ -0,0 +1,31 @@
+package net
+
+import (
+	"fmt"
+
+	"github.com/cosmos/cosmos-sdk/client/context"
+	ethermint "github.com/cosmos/ethermint/types"
+)
+
+// PublicNetAPI is the eth_ prefixed set of APIs in the Web3 JSON-RPC spec.
+type PublicNetAPI struct {
+	networkVersion uint64
+}
+
+// NewAPI creates an instance of the public Net Web3 API.
+func NewAPI(clientCtx context.CLIContext) *PublicNetAPI {
+	// parse the chainID from a integer string
+	chainIDEpoch, err := ethermint.ParseChainID(clientCtx.ChainID)
+	if err != nil {
+		panic(err)
+	}
+
+	return &PublicNetAPI{
+		networkVersion: chainIDEpoch.Uint64(),
+	}
+}
+
+// Version returns the current ethereum protocol version.
+func (api *PublicNetAPI) Version() string {
+	return fmt.Sprintf("%d", api.networkVersion)
+}