CODEOWNERS: Add myself as an owner of ext/ffi, ext/opcache and the core Zend files

Author: dstogov

CODEOWNERS

@@ -9,6 +9,25 @@
 # https://docs.github.com/en/repositories/managing-your-repositorys-settings-and-features/customizing-your-repository/about-code-owners
 
 /.github @iluuu1994
-/ext/opcache @iluuu1994
+/ext/ffi @dstogov
+/ext/opcache @dstogov @iluuu1994
 /ext/random @TimWolla
 /Zend @iluuu1994
+/Zend/Optimizer @dstogov
+/Zend/zend.* @dstogov
+/Zend/zend_alloc.* @dstogov
+/Zend/zend_API.* @dstogov
+/Zend/zend_closures.* @dstogov
+/Zend/zend_execute.* @dstogov
+/Zend/zend_execute_API.c @dstogov
+/Zend/zend_gc.* @dstogov
+/Zend/zend_hash.* @dstogov
+/Zend/zend_inheritance.* @dstogov
+/Zend/zend_object_handlers.* @dstogov
+/Zend/zend_objects.* @dstogov
+/Zend/zend_objects_API.* @dstogov
+/Zend/zend_opcode.* @dstogov
+/Zend/zend_string.* @dstogov
+/Zend/zend_type*.h @dstogov
+/Zend/zend_variables.* @dstogov
+/Zend/zend_vm* @dstogov