Category, group and subgroup support

[NullMember]

Basic category, group and subgroup support. Group and subgroup automatically hides nodes under them.

[4d49]

I found the problem. If you collapse/expand a group, subgroups will be expanded, but the button state will not be pressed and will need to be pressed twice.

[NullMember]

Last commit should fix the issue

[4d49]

The test_1 property is always hidden in the inspector .

@export_category("Сategory")

@export_group("The property is always hidden")
@export var test_1: bool = true

@export_subgroup("In a subgroup, everything works")
@export var test_2: bool = true

[4d49]

A radical solution to the problem would be to add properties as child nodes to categories/groups. But then there is the problem of finding properties.