M3: component properties keep their order on rename; Make slot asks for the name (#1536, #1537) (#1565)

Properties were listed by name, so a rename moved one. Components now keep prop_order (the names as they were made; a rename keeps the place) and every listing follows it. Make slot opens a name field under the frame's Slot row; Enter makes the slot, Escape cancels, a taken name keeps the field open.

crates/engine/src/lib.rs

@@ -427,6 +427,8 @@ pub(crate) mod plugins_tests;
 #[cfg(test)]
 mod progressive_blur_tests;
 #[cfg(test)]
+mod prop_order_tests;
+#[cfg(test)]
 mod property_copy_tests;
 #[cfg(test)]
 mod proto_behaviour_tests;