[ticket/12466] Move classes from acp_database.php to their own files

* Moving classes from acp_database.php to phpbb/db/extractor namespace,
   also into separate files
 * Adding DocBlocks and property visibility to classes
 * Removing globals from code
 * Passing former globals to base_extractor's constructor
 * Adding DB extractor as a service, also implementing the extractor interface
   as well as the extractor factory.

PHPBB3-12466

phpBB/config/default/container/services_db.yml

@@ -19,6 +19,67 @@ services:
         arguments:
             - @dbal.conn.driver
 
+# ----- DB Extractor -----
+    dbal.extractor.factory:
+        class: phpbb\db\extractor\factory
+        arguments:
+            - @dbal.conn.driver
+            - @service_container
+
+    dbal.extractor:
+        class: phpbb\db\extractor\extractor_interface
+        factory: ["@dbal.extractor.factory", get]
+
+# ----- DB Extractors for different drivers -----
+# Scope MUST be prototype for all the handlers to work correctly.
+    dbal.extractor.extractors.mssql_extractor:
+        class: phpbb\db\extractor\mssql_extractor
+        scope: prototype
+        arguments:
+            - %core.root_path%
+            - @request
+            - @dbal.conn.driver
+
+    dbal.extractor.extractors.mysql_extractor:
+        class: phpbb\db\extractor\mysql_extractor
+        scope: prototype
+        arguments:
+            - %core.root_path%
+            - @request
+            - @dbal.conn.driver
+
+    dbal.extractor.extractors.oracle_extractor:
+        class: phpbb\db\extractor\oracle_extractor
+        scope: prototype
+        arguments:
+            - %core.root_path%
+            - @request
+            - @dbal.conn.driver
+
+    dbal.extractor.extractors.postgres_extractor:
+        class: phpbb\db\extractor\postgres_extractor
+        scope: prototype
+        arguments:
+            - %core.root_path%
+            - @request
+            - @dbal.conn.driver
+
+    dbal.extractor.extractors.sqlite3_extractor:
+        class: phpbb\db\extractor\sqlite3_extractor
+        scope: prototype
+        arguments:
+            - %core.root_path%
+            - @request
+            - @dbal.conn.driver
+
+    dbal.extractor.extractors.sqlite_extractor:
+        class: phpbb\db\extractor\sqlite_extractor
+        scope: prototype
+        arguments:
+            - %core.root_path%
+            - @request
+            - @dbal.conn.driver
+
 # ----- Migrator -----
     migrator:
         class: phpbb\db\migrator