Align GLU implementation with LLaMa

[vchiley]

Align LLM-Foundry GLU implementation with LLaMa implementation
ie

self.down_proj(self.act(self.gate_proj(x)) * self.up_proj(x))

instead of

self.down_proj(self.act(self.up_proj(x)) * self.gate(x))

Additionally, with #805, we are no longer constricted to using gelus. Therefore it's no longer GeGLU, but ANY_ACT_FN_GLU, so I'm changing the name to generic GLU.