Throw a warning when exporting if a mesh has a high vertex count

[Pherakki]

Provide details on the proposal. The plugin should be aware if a mesh has a potentially-problematic number of vertices. The proposal is to have an additional export option, accessible via dropdown:

• Ignore
• Warn
• Error + Select

If a mesh is detected to have more than 6192 vertices (since this is roughly the limit where problems sometimes start occurring), the plugin should either:

• Do nothing about it (Ignore)
• Add a warning to the export report saying that meshes XYZ have more than 6192 vertices
• Throw an error that prevents export and highlights whichever meshes have more than 6192 vertices.

The default should also be configurable from the preferences.

Is your feature request related to a problem? Please describe. Sometimes meshes with >6k vertices behave unexpected in-game. A warning that says this might happen, since the ultimate cause is unknown, would help.

Additional context No further details required.

[Pherakki]

Implemented in 2b1d1603e43f63e02b7b3018f3a0d6aaa2af8cf9