Enhance session handling and introduce session flags

src/Socialbox/Enums/Flags/SessionFlags.php

@@ -0,0 +1,21 @@
+<?php
+
+    namespace Socialbox\Enums\Flags;
+
+    enum SessionFlags : string
+    {
+        // Verification, require fields
+        case VER_SET_PASSWORD = 'VER_SET_PASSWORD'; // Peer has to set a password
+        case VER_SET_OTP = 'VER_SET_OTP'; // Peer has to set an OTP
+        case VER_SET_DISPLAY_NAME = 'VER_SET_DISPLAY_NAME'; // Peer has to set a display name
+
+        // Verification, verification requirements
+        case VER_EMAIL = 'VER_EMAIL'; // Peer has to verify their email
+        case VER_SMS = 'VER_SMS'; // Peer has to verify their phone number
+        case VER_PHONE_CALL = 'VER_PHONE_CALL'; // Peer has to verify their phone number via a phone call
+        case VER_IMAGE_CAPTCHA = 'VER_IMAGE_CAPTCHA'; // Peer has to solve an image captcha
+
+        // Login, require fields
+        case VER_PASSWORD = 'VER_PASSWORD'; // Peer has to enter their password
+        case VER_OTP = 'VER_OTP'; // Peer has to enter their OTP
+    }