Added support for gaussian splatting ply file save

[ironjr]

Issue

Although the output of the system is a Gaussian splatting, it does not save the file into a standardized format. Which means additional routines are required to visualize the result in the other Gaussian splatting visualizer.

Changes

• Added requirements for plyfile==0.8.1 for Gaussian splatting support.
• In utils/common_utils.py, added additional procedure for converting params.npz into gsplat.ply. Conversion does not preserve every information, e.g., trajectory is not recorded in Gaussian splatting format.
• Changed a single character typo in README.md

Related issue

https://github.com/spla-tam/SplaTAM/issues/22

[Nik-V9]

Thanks for this pull request! It has been merged in: https://github.com/spla-tam/SplaTAM/pull/78