feat: added implementation of HeadHunter hook for user registration

JOBot.Backend/appsettings.json

@@ -9,6 +9,17 @@
     "ConnectionStrings": {
         "PostgreSQL": "Host=postgres;Port=5432;Database=jobot;Username=postgres;Password=LocalDbPass"
     },
+    "HeadHunter": {
+        "Links": {
+            "AuthLink": "https://hh.ru/oauth/authorize?response_type=code&client_id={client_id}&redirect_uri={redirect_uri}",
+            "HookDomain": "jobot.lisoveliy.su",
+            "HookRoute": "/auth",
+            "HeadHunterApiDomain": "api.hh.ru",
+            "HeadHunterTokenRoute": "/token"
+        },
+        "ClientId": "",
+        "Secret": ""
+    },
     "Kestrel": {
         "Endpoints": {
             "gRPC": {