Add gpu support for harmonypy

[ghar1821]

Harmonypy now supports gpu. Will be good to convert the cpu implementation to gpu.

[LuLeom]

@ghar1821 As far as I understood harmonypy v2.0.0 should match the new harmony2 R implementation.

I think It could be a matter of just specifying the version in the config file, as the API does not seem to be changed.
I do not know if OP supports gpu usage though