Update use statement lists with new Friendica\Database\dba class

- Remove unused use statement
- Remove superfluous use statements (classes in the same namespace)
- Add missing use statements

src/Database/DBM.php

@@ -4,7 +4,6 @@
  */
 namespace Friendica\Database;
 
-use dba;
 use Friendica\Util\DateTimeFormat;
 
 require_once 'include/dba.php';

src/Database/DBStructure.php

@@ -4,7 +4,8 @@
  */
 namespace Friendica\Database;
 
-use dba;
+use Exception;
+use Friendica\Core\Addon;
 use Friendica\Core\Config;
 use Friendica\Core\L10n;
 
@@ -629,7 +630,7 @@ class DBStructure
 	private static function createIndex($indexname, $fieldnames, $method = "ADD") {
 		$method = strtoupper(trim($method));
 		if ($method!="" && $method!="ADD") {
-			throw new \Exception("Invalid parameter 'method' in self::createIndex(): '$method'");
+			throw new Exception("Invalid parameter 'method' in self::createIndex(): '$method'");
 		}
 
 		if ($fieldnames[0] == "UNIQUE") {
@@ -1941,7 +1942,7 @@ class DBStructure
 						]
 				];
 
-		\Friendica\Core\Addon::callHooks('dbstructure_definition', $database);
+		Addon::callHooks('dbstructure_definition', $database);
 
 		return $database;
 	}

src/Database/PostUpdate.php

@@ -5,11 +5,9 @@
 namespace Friendica\Database;
 
 use Friendica\Core\Config;
-use Friendica\Database\DBM;
 use Friendica\Model\Contact;
 use Friendica\Model\Item;
 use Friendica\Model\PermissionSet;
-use dba;
 
 require_once 'include/dba.php';