Adds the option to create a boolean socket that can be used as a panel toggle.
This allows creating simpler and more compact node group UIs when a panel
can be "disabled".
The toggle input is a normal input socket that is just drawn a bit differently in
the UI. Whether a boolean is a toggle input or not does not affect evaluation.
Also see #133936 for guides on how to add and remove panel toggles.
Pull Request: https://projects.blender.org/blender/blender/pulls/133936
2822777f13