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

abci/client/socket_client.go

@@ -14,6 +14,7 @@ import (
 	"github.com/tendermint/tendermint/abci/types"
 	cmn "github.com/tendermint/tendermint/libs/common"
 	"github.com/tendermint/tendermint/libs/service"
+	"github.com/tendermint/tendermint/libs/timer"
 )
 
 const reqQueueSize = 256 // TODO make configurable
@@ -33,7 +34,7 @@ type socketClient struct {
 	conn        net.Conn
 
 	reqQueue   chan *ReqRes
-	flushTimer *cmn.ThrottleTimer
+	flushTimer *timer.ThrottleTimer
 
 	mtx     sync.Mutex
 	err     error
@@ -45,7 +46,7 @@ type socketClient struct {
 func NewSocketClient(addr string, mustConnect bool) *socketClient {
 	cli := &socketClient{
 		reqQueue:    make(chan *ReqRes, reqQueueSize),
-		flushTimer:  cmn.NewThrottleTimer("socketClient", flushThrottleMS),
+		flushTimer:  timer.NewThrottleTimer("socketClient", flushThrottleMS),
 		mustConnect: mustConnect,
 
 		addr:    addr,