EXAMPLE Op fusion

[LPanosTT]

In this PR I've created a fusion pass and added a few patterns. They are:

• Fuse exp(x) / sum(exp(x)) to softmax(x)
• Fuse reshape(reduce(x)) to reduce(x) if the target shape of the reshape is equivalent to just setting the keepdim attribute of reduce to true/false (We'll have to disable this one until we get a metal uplift)
• Fuse broadcast(x) to x when the broadcast does nothing
• Fuse maximum(x, 0) to relu(x)

Issue: #1059

I do not expect this to be upstreamed to main anytime soon if ever. I was hoping this could be a used as an example.