feat!: add telegram auth and async refactor

- Removed "/schedule/update-download-url" endpoint, this mechanism was replaced by Yandex Cloud FaaS. Ура :)
- Improved schedule caching mechanism.
- Added Telegram WebApp authentication support.
- Reworked endpoints responses and errors mechanism.
- Refactored application state management.
- Make synchronous database operations, middlewares and extractors to asynchronous.
- Made user password field optional to support multiple auth methods.
- Renamed users table column "version" to "android_version" and made it nullable.

src/database/schema.rs

@@ -21,12 +21,13 @@ diesel::table! {
     users (id) {
         id -> Text,
         username -> Text,
-        password -> Text,
+        password -> Nullable<Text>,
         vk_id -> Nullable<Int4>,
-        access_token -> Text,
-        group -> Text,
+        access_token -> Nullable<Text>,
+        group -> Nullable<Text>,
         role -> UserRole,
-        version -> Text,
+        android_version -> Nullable<Text>,
+        telegram_id -> Nullable<Int8>,
     }
 }