Adds a Join Bundle node with a multi-input Bundle socket. Bundles are
iterated on the top level of each input bundle and items added to the resulting
single bundle. While creating the final bundle existing items have priority and
new items with an already existing name are discarded.
There is an info message when there are duplicate keys in the input bundles.
Co-authored-by: Brady Johnston
Co-authored-by: Jacques Lucke
Pull Request: https://projects.blender.org/blender/blender/pulls/146750