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.

api4/websocket.go

@@ -4,12 +4,12 @@
 package api4
 
 import (
+	"fmt"
 	"net/http"
 
-	l4g "github.com/alecthomas/log4go"
 	"github.com/gorilla/websocket"
+	"github.com/mattermost/mattermost-server/mlog"
 	"github.com/mattermost/mattermost-server/model"
-	"github.com/mattermost/mattermost-server/utils"
 )
 
 func (api *API) InitWebSocket() {
@@ -25,7 +25,7 @@ func connectWebSocket(c *Context, w http.ResponseWriter, r *http.Request) {
 
 	ws, err := upgrader.Upgrade(w, r, nil)
 	if err != nil {
-		l4g.Error(utils.T("api.web_socket.connect.error"), err)
+		mlog.Error(fmt.Sprintf("websocket connect err: %v", err))
 		c.Err = model.NewAppError("connect", "api.web_socket.connect.upgrade.app_error", nil, "", http.StatusInternalServerError)
 		return
 	}