Consider disallowing `DELETE FROM` and `UPDATE` queries without explicit `WHERE` clauses

[despawnerer]

Generally speaking, people may want to delete everything, so they should have an option to do that. But that's a relatively rare case and the default can be safer:

delete_from("Dummy").to_string();  // ❌ should not compile
delete_from("Dummy").all().to_string();  // ✅ good, explicitly deletes everything
delete_from("Dummy").where_("x > 1").to_string();  // ✅ good, explicitly has a condition