Add GUI Page type to pl_page_types for Modifiers

[DoobesURU]

I noticed this while working on getting face/swivel mods working for Empty objects (another issue). The modifier properties use room and gui in pl_page_types to determine which modifier can work in which type of page. I found this wasn't working completely due to a missing reference in the base.py script. This fix adds the reference and gets the missing modifiers working for GUIs, such as the Advanced mod for Python scripts.

[DoobesURU]

Note that I purposely excluded "external" for obvious reasons. 😉

[dpogue]

I'm not sure that swivel mods make sense on objects that are part of a GUI? What was your use case here?

[DoobesURU]

I'm not sure that swivel mods make sense on objects that are part of a GUI? What was your use case here?

No, sorry. As I said, that's a separate issue. I just happened to notice it while digging in the scripts for it. This is just a fix to use the existing modifier definitions in the associated scripts in properties/modifiers/.

[Hoikas]

This doesn't look quite right to me... My thinking was that only a very narrow set of modifiers would be useful in a GUI page, so, by default, we would only make a modifier available to room pages. Modifiers need to opt-into being available for gui pages. If there's any modifier that should be available in a GUI page but isn't, we'll want to add pl_page_types = {"room", "gui"} to that modifier specifically.

[DoobesURU]

This doesn't look quite right to me... My thinking was that only a very narrow set of modifiers would be useful in a GUI page, so, by default, we would only make a modifier available to room pages. Modifiers need to opt-into being available for gui pages. If there's any modifier that should be available in a GUI page but isn't, we'll want to add pl_page_types = {"room", "gui"} to that modifier specifically.

That seems to be already implemented into each script in properties/modifier already. This, as far as I can tell, is telling the base.py script to use those existing definitions in the other scripts. /shrug

[dpogue]

Adding the "gui" option to a specific modifier worked for me in #416