Issue #3098588: Fix the Sitemap Entities form to work more like expected.
- Do not extend ConfigFormBase since this is a form that touches many different configuration files.
- Enabling a bundle's checkbox will actually set that type to be included in the sitemap. Previously: the type would be excluded.
- Disabling a bundle's checkbox will not just update the config settings to set status to false, instead of deleting the config. This will prevent the link data from being removed from the table.