Completely restored authorization_code grant for user side.

Reworked oauth_sessions table.
Added extension to use MariaDB's JSON columns.
Rewritten tests for authorization_code grant for client side.
Deprecate some old shit.
[skip ci]

api/tests/functional/dev/applications/DeleteClientCest.php

@@ -0,0 +1,30 @@
+<?php
+declare(strict_types=1);
+
+namespace api\tests\functional\dev\applications;
+
+use api\tests\_pages\OauthRoute;
+use api\tests\FunctionalTester;
+
+class DeleteClientCest {
+
+    /**
+     * @var OauthRoute
+     */
+    private $route;
+
+    public function _before(FunctionalTester $I) {
+        $this->route = new OauthRoute($I);
+    }
+
+    public function testDelete(FunctionalTester $I) {
+        $I->amAuthenticated('TwoOauthClients');
+        $this->route->deleteClient('first-test-oauth-client');
+        $I->canSeeResponseCodeIs(200);
+        $I->canSeeResponseIsJson();
+        $I->canSeeResponseContainsJson([
+            'success' => true,
+        ]);
+    }
+
+}