Adding scene alignment & normalization across datasets

[gauravpradeep]

This PR adds axis alignment and zero-centering for all scene pointclouds across datasets, similar to how Sceneverse preprocesses scene pointclouds, since we use their language referrals. As reported by Sceneverse, these preprocessing steps help counter changes in data collection settings, such as sensors used, across datasets. We can now evaluate the effect this preprocessing has on our results across all datasets.