Add support for volumetric wireframes

[DmitriySalnikov]

By this I mean adding the ability to draw not only lines one pixel thick, but also thick, volumetric lines
.
Problem:
For example, in the ideal conditions of a test scene, everything is visible well, but in a scene with a large number of light objects, thin lines will be poorly visible.

Solution:
Draw lines using X-like shapes of the desired thickness.

The idea of implementation:
In the project settings, set the default thickness. If the thickness is greater than zero, then use volumetric lines when calling any draw_* function. And also before calling the draw_* function, you can specify the desired thickness by calling, for example, set_line_thickness. And after reset_line_thickness.

Other ways to solve this problem: increase the number of arguments of all functions, or make duplicates of all functions, but for volumetric lines.

Pros:

• Better visibility.
• More understanding of the volume and position in the space of the geometry.

Cons:

• More mesh instances are needed for rendering.
• Adding to the rendering queue is slower.

I hope to do this soon, but in the meantime I would like to see ideas and suggestions.
Or maybe there is an easier way to draw thick lines?..

[DmitriySalnikov]

Implemented in f96700b