Update and cleanup package

[pluflou]

• modernized package with pyproject.toml
  • added optional deps for meme to handle tests locally vs in forks vs on main repo GHA
  • added package versioning from git using setuptools-scm
• cleaned up github actions workflows
  • renamed jobs for clarity
  • added option to run jobs on forks w/o meme. meme dependent tests will be skipped depending on which repo is running them.
  • added useful/pretty summary output for GHA test results
• updated README
• fixed a few typos

Note that with this structure, the dependencies go in pyproject.toml(as unpinned as possible), so the library can be installed without running into many issues resolving version constraints. If we want to pin versions for deploying on certain machines, the requirements.txt should be used with exact version pinning (equivalent to an environment.yml file with conda). For building and releasing (e.g. to PyPI), the pyproject.toml is used.