Python package with expanded testing

[pchakraborty]

This PR addresses some of the concerns raised in #273

• mepo is now a Python package with

  • src/mepo/__init__.py
  • src/mepo/main.py -> src/mepo/__main__.py. This allows one to execute mepo via python -m mepo.

• src/mepo/config/config_file.py -> src/mepo/registry.py. So components.yaml is now called a registry, instead of a config file. While this change is mostly internal, it does affect the clone command - the optional argument --config to mepo clone is now --registry.

• More code reorganization

  • Using Python3's relative import
  • Code from src/mepo/command/command.py is now included in __main__.py
  • src/mepo/command/<command>/<command>.py -> src/mepo/command/<command>.py
    • subcommands are in files src/command/<command_subcommand>.py
  • src/mepo/state/state.py -> src/mepo/state.py
  • src/mepo/state/component.py -> src/mepo/component.py
  • src/mepo/repository/git.py -> src/mepo/git.py
  • Added optional argument -1/--one-per-line for mepo list

• Expanded testing to cover more mepo commands

• Since the multiprocessing library now supports the context manager protocol, we can write

  import multiprocessing as mp
  with mp.Pool() as pool:
      result = pool.map(check_component_status, allcomps)

  3412ad7, 376baf2

• Added linting via Pylint

• Implemented context manager for os.chdir. We can now do

  from mepo.utilities import chdir as mepo_chdir
  with mepo_chdir(some_path):
      execute_some_command()

  instead of

   import os
   cwd = os.getcwd()
   os.chdir(some_path)
   execute_some_command()
   os.chdir(cwd)

  Using contextlib.chdir when available (3.11+)

• Formatted code using Black

• Managing project using Poetry. Closes Poetry for packaging and dependency management  #281

• Split GitHub actions workflow into three

  • Run mepo tests
  • Run formatter
  • Run linter

• Using contextlib.redirect_stdout to redirect stdout to variable

• Switched state file format from pickled (mepo1 style) to json (mepo2 style). Closes State file: pickle to json #284

  • If mepo1 style state is detected, print warning and suggest running mepo update-state
  • Added a new command update-state to permanently convert mepo1 style state to mepo2 style

[pchakraborty]

@mathomp4 I think this is ready for merge. Converting to PR.

[mathomp4]

Approve!