Use PDO for MySQL queries (#8935)

Gut dbFacile
mres() now does nothing... could have some vulnerable queries, but most are ok

TODO
- [x] IRC client broke
- [x] Install broke

DO NOT DELETE THIS TEXT

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tests/DBSetupTest.php

@@ -113,21 +113,10 @@ class DBSetupTest extends DBTestCase
 
     public function testSqlMode()
     {
-        global $sql_mode;
-        $this->assertNotNull($sql_mode, 'Query to save SQL Mode in bootstrap.php failed');
-
-        // sql_mode can only be set by users with access
-        $access = array(
-            'GRANT ALL PRIVILEGES ON *.*',
-            'SUPER'
+        $this->assertEquals(
+            'ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION',
+            dbFetchCell("SELECT @@sql_mode")
         );
-
-        if (str_contains(join(PHP_EOL, dbFetchColumn('SHOW GRANTS')), $access)) {
-            $this->assertEquals(
-                array('ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION'),
-                dbFetchColumn("SELECT @@global.sql_mode")
-            );
-        }
     }
 
     public function testValidateSchema()