Add squeeze_dims function

[agelas]

Feature description

Add a squeeze_dims function, similar to unsqueeze_dims. Specifically, this should adhere closer to the specifications in ONNX/PyTorch, which means

1. Multiple dimensions to squeeze can be passed in as arguments
2. Negative indices can be passed in (ie count from the back)
3. No dimensions at all can be passed in (squeeze all singleton dimensions)

Feature motivation

This reduces friction importing from ONNX graphs and aligns burn closer to pre-existing solutions people might be used to.