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.

store/sqlstore/channel_store.go

@@ -11,9 +11,9 @@ import (
 	"strconv"
 	"strings"
 
-	l4g "github.com/alecthomas/log4go"
 	"github.com/mattermost/gorp"
 	"github.com/mattermost/mattermost-server/einterfaces"
+	"github.com/mattermost/mattermost-server/mlog"
 	"github.com/mattermost/mattermost-server/model"
 	"github.com/mattermost/mattermost-server/store"
 	"github.com/mattermost/mattermost-server/utils"
@@ -852,7 +852,7 @@ func (s SqlChannelStore) IsUserInChannelUseCache(userId string, channelId string
 	}
 
 	if result := <-s.GetAllChannelMembersForUser(userId, true); result.Err != nil {
-		l4g.Error("SqlChannelStore.IsUserInChannelUseCache: " + result.Err.Error())
+		mlog.Error("SqlChannelStore.IsUserInChannelUseCache: " + result.Err.Error())
 		return false
 	} else {
 		ids := result.Data.(map[string]string)