libs/common: Refactor libs/common 4 (#4237)

* libs/common: Refactor libs/common 4

- move byte function out of cmn to its own pkg
- move tempfile out of cmn to its own pkg
- move throttletimer to its own pkg

ref #4147

Signed-off-by: Marko Baricevic <marbar3778@yahoo.com>

* add changelog entry

* fix linting issues

privval/file.go

@@ -9,7 +9,9 @@ import (
 
 	"github.com/tendermint/tendermint/crypto"
 	"github.com/tendermint/tendermint/crypto/ed25519"
+	tmbytes "github.com/tendermint/tendermint/libs/bytes"
 	cmn "github.com/tendermint/tendermint/libs/common"
+	"github.com/tendermint/tendermint/libs/tempfile"
 	"github.com/tendermint/tendermint/types"
 	tmtime "github.com/tendermint/tendermint/types/time"
 )
@@ -56,7 +58,7 @@ func (pvKey FilePVKey) Save() {
 	if err != nil {
 		panic(err)
 	}
-	err = cmn.WriteFileAtomic(outFile, jsonBytes, 0600)
+	err = tempfile.WriteFileAtomic(outFile, jsonBytes, 0600)
 	if err != nil {
 		panic(err)
 	}
@@ -67,11 +69,11 @@ func (pvKey FilePVKey) Save() {
 
 // FilePVLastSignState stores the mutable part of PrivValidator.
 type FilePVLastSignState struct {
-	Height    int64        `json:"height"`
-	Round     int          `json:"round"`
-	Step      int8         `json:"step"`
-	Signature []byte       `json:"signature,omitempty"`
-	SignBytes cmn.HexBytes `json:"signbytes,omitempty"`
+	Height    int64            `json:"height"`
+	Round     int              `json:"round"`
+	Step      int8             `json:"step"`
+	Signature []byte           `json:"signature,omitempty"`
+	SignBytes tmbytes.HexBytes `json:"signbytes,omitempty"`
 
 	filePath string
 }
@@ -127,7 +129,7 @@ func (lss *FilePVLastSignState) Save() {
 	if err != nil {
 		panic(err)
 	}
-	err = cmn.WriteFileAtomic(outFile, jsonBytes, 0600)
+	err = tempfile.WriteFileAtomic(outFile, jsonBytes, 0600)
 	if err != nil {
 		panic(err)
 	}