Add part categories to 3DViewer Preferences dialogue

[trevorsandy]

Subject

Streamline part lookup with categories dialogue allowing custom part categories.
This capability can be quite useful when working with custom parts or substitute parts or helper parts.

Environment

Version of LPub3D - 2.3.1
Operating system - All

Expected behaviour

Ability to define and refine part categories to improve part lookup flexibility speed and efficiency

Actual behaviour

If the intended lookup part is not in any of the predefined categories, the user must select the 'all parts' category which is inefficient and sometimes slows down the application.

Solution

Enable the part categories dialogue which allows setting custom part categories.

[trevorsandy]

Implemented.