[#2762] added Yandex OAuth2 provider

Co-authored-by: Valentine <xb2w1z@gmail.com>

ui/src/providers.js

@@ -31,6 +31,11 @@ export default [
         logo:  "microsoft.svg",
         optionsComponent: MicrosoftOptions,
     },
+    {
+        key:   "yandexAuth",
+        title: "Yandex",
+        logo:  "yandex.svg",
+    },
     {
         key:   "facebookAuth",
         title: "Facebook",