Three.js WebGL - Migrate from Geometry to BufferGeometry

[andreasrosdal]

The FCW code needs to be migrated to use BufferGeometry instead of Geometry, in order to update to recent Three.js versions.

PlaneGeometry shoud be migrated to BufferGeometry here:
https://github.com/freeciv/freeciv-web/blob/develop/freeciv-web/src/main/webapp/javascript/webgl/mapview.js#L179

FCW currently at Three.js version r124. Latest is r135.

A description about how to do this is documented here:
https://sbcode.net/threejs/geometry-to-buffergeometry/

See #336

[andreasrosdal]

Fixed in https://www.fciv.net https://github.com/fciv-net/fciv-net