Error and Audit logger webhooks (#1855)

Similar to MinIO now it's possible to configure webhooks to log all
triggered errors and incomming requests via env variables:

```
CONSOLE_LOGGER_WEBHOOK_ENABLE_<ID>
CONSOLE_LOGGER_WEBHOOK_ENDPOINT_<ID>
CONSOLE_LOGGER_WEBHOOK_AUTH_TOKEN_<ID>
CONSOLE_LOGGER_WEBHOOK_CLIENT_CERT_<ID>
CONSOLE_LOGGER_WEBHOOK_CLIENT_KEY_<ID>
CONSOLE_LOGGER_WEBHOOK_QUEUE_SIZE_<ID>

CONSOLE_AUDIT_WEBHOOK_ENABLE_<ID>
CONSOLE_AUDIT_WEBHOOK_ENDPOINT_<ID>
CONSOLE_AUDIT_WEBHOOK_AUTH_TOKEN_<ID>
CONSOLE_AUDIT_WEBHOOK_CLIENT_CERT_<ID>
CONSOLE_AUDIT_WEBHOOK_QUEUE_SIZE_<ID>
```

Signed-off-by: Lenin Alevski <alevsk.8772@gmail.com>

restapi/logs.go

@@ -18,6 +18,7 @@
 package restapi
 
 import (
+	"context"
 	"errors"
 	"log"
 	"os"
@@ -36,10 +37,14 @@ func logError(msg string, data ...interface{}) {
 	errorLog.Printf(msg+"\n", data...)
 }
 
+func logIf(ctx context.Context, err error, errKind ...interface{}) {
+}
+
 // globally changeable logger styles
 var (
 	LogInfo  = logInfo
 	LogError = logError
+	LogIf    = logIf
 )
 
 // Context captures all command line flags values