* Dialogs: HTML forms - follow-up
Follow-up to #4264:
- Split `zcl_abapgit_html_form` class
Processing form data has been moved to `zcl_abapgit_html_form_utils`
- `iv_is_main` refactored to `iv_cmd_type`
- In case of unsaved data, form exit will now prompt for confirmation (`zcl_abapgit_html_form_utils`)
* dot space
* lint
* Remove const
Co-authored-by: Lars Hvam <larshp@hotmail.com>