minor bug fixes

[hardik01shah]

Following are the proposed changes: Fix 1: Masking of the depth from a given roi had a mistake in the ply_utils.py file Fix 2: Parameter for mask_module checkpoint location in the config file has been corrected from att_cp_loc to mask_cp_loc.
Fix3: Conversion of pose from quaternion to rotation matrix in the tum_mono and tum_rgbd dataloaders has been fixed. The scipy.spatial.transform.Rotation.from_quat() method takes input in scalar-last format (qx, qy, qz, qw) rather than (qw, qx, qy, qz).