Pymap3d

[microseconds added to juliandate](https://github.com/geospace-code/pymap3d/commit/9310f624bbc8e445b0bd577a0e1aa48c2b34b67d)


[Fixed numpy divide by zero error converting ECEF for multiple locations.](https://github.com/geospace-code/pymap3d/commit/e847c327f7865148d6e13f2bb2974eda8c467af9)


[Don't skip Beta calculation if some values would divide-by-zero.](https://github.com/geospace-code/pymap3d/commit/3e4908ff99ea7f7c7b90dc86fb0dfe139c1a9186)

[vdist, vreckon: add deg= option (default true)](https://github.com/geospace-code/pymap3d/commit/343a786f2de12164a4fc2dc0c2942e926ba77aaa)

[ecef2geodetic: scalar-in, scalar-out](https://github.com/geospace-code/pymap3d/commit/dc652b8944f8d5d2e746baadfa8ead80c6438184)

use `warnings.catch_warnings()` context manager instead of `numpy.seterr` to avoid breaking other programs that `import pymap3d` and want their warnings not to be errors.

Thanks sanguinariojoe for the report and suggested fix

* Numpy would issue warnings that could cause incorrect computations by not being caught in `try: except:` for things like divide by zero. This has been fixed.
* overhaul the Ellipsoid() class
* apply good coding style and use only pyproject.toml (no setup.py, setup.cfg)
* Require Python >= 3.8: Numpy NEP29 dropped support for Python < 3.8 in December 2021.
We are having a harder time supporting corner cases in Python 3.7.

thanks EpicWink

lookAtSpheroid allows all inputs to be arrays of same shape

add functions `spherical2geodetic`, `geodetic2spherical` thanks [leouieda](https://github.com/geospace-code/pymap3d/issues?q=is%3Apr+author%3Aleouieda)

remove internal "use_astropy" option

add mathfun.py to abstract numpy/math fallback

The type hinting for most numerics was removed to avoid causing external package problems as per 50. thanks randallpittman
The CI coverage was improved by testing each supported Python version across MacOS, Linux, and Windows.
The PEP621 pyproject.toml meta was removed to avoid duplication and conflicts with setup.cfg. thanks philblckwd