#1221 Include arm64 version of libj3dcore-ogl.so for Linux

[Nim van der Schee]

The only thing missing for SweetHome3D on Linux/arm64 (or aarch64) is a libj3dcore-ogl.so for the right platform. For now, an i386 and an amd64 are included.

I'm not sure exactly how the build system works but I was able to run SweetHome3D without issue on ARM64 by just swapping the amd64 libj3dcore-ogl.so with an arm64 version shipped by Ubuntu (https://launchpad.net/ubuntu/focal/+source/java3d).

So I suggest SweetHome3D should ship it as well and use it as appropriate.