Split DBStructure & View to avoid DB-calls and dependencies for basic operations

- new "Definition" classes vor DB and Views
- new "Writer" classes to create SQL definitions for DB and Views
- DBStructure & View are responsible to execute DB-querys

src/Model/GServer.php

@@ -2075,7 +2075,7 @@ class GServer
 	 */
 	public static function update(array $fields, array $condition): bool
 	{
-		$fields = DBStructure::getFieldsForTable('gserver', $fields);
+		$fields = DI::dbaDefinition()->getFieldsForTable('gserver', $fields);
 
 		return DBA::update('gserver', $fields, $condition);
 	}