Write meta data to pymuhrec

[anderskaestner]

Enter meta data in package/pyproject.toml

[damskii9992]

An example of how to fill in the metadata of the pyproject.toml file is shown at https://packaging.python.org/en/latest/guides/writing-pyproject-toml/ together with descriptions of the various fields. The most important fields are the authors/maintainers with emails, the version, the description, the readme and the license. Additional fields to possibly fill out are keywords, classifiers and urls.