Migrate config to KV data format (#8392)

- adding oauth support to MinIO browser (#8400) by @kanagaraj
- supports multi-line get/set/del for all config fields
- add support for comments, allow toggle
- add extensive validation of config before saving
- support MinIO browser to support proper claims, using STS tokens
- env support for all config parameters, legacy envs are also
  supported with all documentation now pointing to latest ENVs
- preserve accessKey/secretKey from FS mode setups
- add history support implements three APIs
  - ClearHistory
  - RestoreHistory
  - ListHistory
- add help command support for each config parameters
- all the bug fixes after migration to KV, and other bug
  fixes encountered during testing.

cmd/bucket-notification-handlers.go

@@ -92,7 +92,7 @@ func (api objectAPIHandlers) GetBucketNotificationHandler(w http.ResponseWriter,
 		}
 	}
 
-	config.SetRegion(globalServerConfig.GetRegion())
+	config.SetRegion(globalServerRegion)
 
 	// If xml namespace is empty, set a default value before returning.
 	if config.XMLNS == "" {
@@ -147,7 +147,7 @@ func (api objectAPIHandlers) PutBucketNotificationHandler(w http.ResponseWriter,
 	}
 
 	var config *event.Config
-	config, err = event.ParseConfig(io.LimitReader(r.Body, r.ContentLength), globalServerConfig.GetRegion(), globalNotificationSys.targetList)
+	config, err = event.ParseConfig(io.LimitReader(r.Body, r.ContentLength), globalServerRegion, globalNotificationSys.targetList)
 	if err != nil {
 		apiErr := errorCodes.ToAPIErr(ErrMalformedXML)
 		if event.IsEventError(err) {