Update repo's layout

[GuillemBarroso]

Fix #296.

Using the dev guide recommendations and other PyAnsys repos, I tried to address issue #296.

Changes:

• Move ansys/dpf/core inside src/ directory.
• Add tox.ini and .pre-commit-config.yaml.
• Use pyproject.toml instead of setup.py
• Since pyproject.toml handles the version as well, I have removed the _version.py and added the server versions in __init__.py.

The only change that will be needed after this is to rename the branch master to main.

[jorgepiloto]

Just left some minor comments. This is looking good, @GuillemBarroso.

[codecov]

Codecov Report

Merging #627 (b2a162f) into master (b2a162f) will not change coverage.
The diff coverage is n/a.

❗ Current head b2a162f differs from pull request most recent head 33b03d5. Consider uploading reports for the commit 33b03d5 to get more accurate results

@@           Coverage Diff           @@
##           master     #627   +/-   ##
=======================================
  Coverage   86.63%   86.63%           
=======================================
  Files          69       69           
  Lines        7750     7750           
=======================================
  Hits         6714     6714           
  Misses       1036     1036           

[jorgepiloto]

Use __name__ here. It avoids hardcoding the namespace of the package:

Suggested change

	__version__ = importlib_metadata.version("ansys-dpf-core")
	__version__ = importlib_metadata.version(__name__.replace(".", "-"))

[GuillemBarroso]

Yes, I had this before. However, I was getting the following error in the Test docstrings step: "importlib.metadata.PackageNotFoundError: core".

With @germa89 we realized that this was fixed by hard-coding the name. I will try to investigate this a bit more.

[germa89]

Normally I would agree with @jorgepiloto ... but in this case, for some reason, we needed to provide the hardcoded package name to avoid import issues.

[GuillemBarroso]

Closing this PR as I was trying to do too many things at once.

In the new PRs I will go one step at a time.