Line extrusion as cylinders

[Neptilo]

Description

Extrude line GIS data in 3D using a diameter value to generate cylindrical geometry. Intended for utilities and linear infrastructures where physical thickness matters.

Motivation and Context

Add support for defining a diameter for lines in the 3D view, useful to model pipes for example.
Implements #2627
Tested on Ubuntu, Firefox.

Screenshots

[Neptilo]

Performance tests

Average durations of calls to Feature2Mesh.featureToExtrudedLine, on the bus lines dataset in source_stream_wfs_3d:

Comparison with/without round caps at line ends - 40 function calls each:

• With flat ends: 334.5 ms
• With round ends: 346.5 ms
• The duration increases by 2 % to 7 % when switching from flat ends to round ends, averaging a 4.5 % increase.

Comparison with visible/invisible globe layer - 60 function calls each:

• Visible: 327 ms
• Invisible: 333 ms

So no significant difference.