Structured logging (#8673)

* Implementing structured logging

* Changes to en.json to allow refactor to run.

* Fixing global logger

* Structured logger initalization.

* Add caller.

* Do some log redirection.

* Auto refactor

* Cleaning up l4g reference and removing dependancy.

* Removing junk.

* Copyright headers.

* Fixing tests

* Revert "Changes to en.json to allow refactor to run."

This reverts commit fd8249e99bcad0231e6ea65cd77c32aae9a54026.

* Fixing some auto refactor strangeness and typo.

* Making keys more human readable.

app/websocket_router.go

@@ -4,10 +4,10 @@
 package app
 
 import (
-	l4g "github.com/alecthomas/log4go"
-
+	"fmt"
 	"net/http"
 
+	"github.com/mattermost/mattermost-server/mlog"
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/utils"
 )
@@ -91,7 +91,7 @@ func (wr *WebSocketRouter) ServeWebSocket(conn *WebConn, r *model.WebSocketReque
 }
 
 func ReturnWebSocketError(conn *WebConn, r *model.WebSocketRequest, err *model.AppError) {
-	l4g.Error(utils.T("api.web_socket_router.log.error"), r.Seq, conn.UserId, err.SystemMessage(utils.T), err.DetailedError)
+	mlog.Error(fmt.Sprintf("websocket routing error: seq=%v uid=%v %v [details: %v]", r.Seq, conn.UserId, err.SystemMessage(utils.T), err.DetailedError))
 
 	err.DetailedError = ""
 	errorResp := model.NewWebSocketError(r.Seq, err)