Rename the repeat nodes to replace "Instance" terminology with "Repeat" (#3794)

* WIP

* Move the Mirror node from the module 'vector' to 'graphic'

* Update demo art

* Fix failing tests

Fix tests

node-graph/nodes/repeat/src/lib.rs

@@ -0,0 +1,8 @@
+pub mod repeat_nodes;
+
+// Re-export for convenience
+pub use core_types as gcore;
+pub use graphic_types;
+pub use raster_types;
+pub use repeat_nodes::*;
+pub use vector_types;