Use hatch and hatch-vcs

[getzze]

closes #1076

• Version is tracked with setuptools_scm via git tags, with a _version.py file created when building the package (it's a mess, no _version.py file is created).
• The source files were moved to src/subliminal to avoid errors while testing.
• Use hatch environments instead of tox for the github actions.
• Update versions of pre-commit hooks.
• Rename the optional dependencies test -> tests. So to install subliminal with the test dependencies, you need to use pip install subliminal[tests]

[getzze]

this PR is too big and should be split into smaller PRs.