Comparison of the radio telescope noise calculation to 21cmSense

The current version of [21cmSense](https://21cmsense.readthedocs.io/en/latest/index.html) provides noise power spectrum for radio telescope. This package creates noise cubes ([noise_model.py](https://github.com/sambit-giri/tools21cm/blob/master/src/tools21cm/noise_model.py)), which can be converted into power spectra. 