- pre-commit from 4.1.0 to 4.3.0,
- codespell from 2.2.1 to 2.2.2,
- black from 22.3.0 to 22.10.0 and
- flake8 from 4.0.1 to 5.0.4. Also freeze flake8 dependencies.

Also change flake8's repo config to github (the gitlab mirror
being outdated).

black is considered stable since release 22.1.0 and the version
we are currently using is quite outdated and not compatible with
click 8.1.0, so it is time to bump it to its latest stable release.

Please note that E501 pycodestyle warning related to line length
is replaced by B950 one from flake8-bugbear as recommended by black.
https://black.readthedocs.io/en/stable/the_black_code_style/current_style.html#line-length

Related to T3922

This also drops:
- spurious copyright headers to those files if present.
- fix a type issue revealed by the new mypy

Related to T3812

Enable to check package documentation can be built without producing
sphinx warnings.

The sphinx environment is designed to be used in continuous integration
in order to prevent breaking documentation build when committing changes.

The sphinx-dev environment is designed to be used inside a full swh
development environment.

Related to T3258

This allows to enforce a specific version of java to be used. For
example, since cassandra seems not to support java 14 yet, this allows
to run tests on bullseye:

  JAVA_HOME=/usr/lib/jvm/java-11-openjdk-amd64/ pytest swh

The current hard-coded value won't work for other distributions not relying on
standard conventions (e.g. nixos...).

This keeps the original behavior and only allow to diverge based on the
environment variable SWH_CASSANDRA_BIN.

This also:
- fixes an issue on log path inexistence which raises.
- renames the other env variable LOG_CASSANDRA to SWH_CASSANDRA_LOG (for
  consistency)

- blackify all the python files,
- enable black in pre-commit,
- add a black tox environment.

With no guarantees on the order or how partitioning is done,
and with the new-style pagination.

As this got migrated back to the swh.lister module

- use pytest instead of unittest.TestCase plumbing
- extract data from the TestStorageData into a data `storage_data` module;
  this module also provide a simple helper `StorageData` class that mimics
  the original class (access by attributes),
- implement a series of pytest fixtures for these storage specific tests,
- get rid of most hypothesis-based tests,
- replace usage of the use_url hypothesis boolean statetgy by
  pytest.mark.parametrize fixtures; this allows to prevent from
  the need of resetting the storage, since tests are truly executed
  twice (thus with a new swh_storage),
- refactor test_db to use pytest-postgresql.

Disable (xfail) tests from test_snapshot.py, test_api_client
and test_in_memory for now.

Fixes/refactorings come with following revisions.

Related D2082

This fixes issues regarding origin/origin_visit

Use: tox -e py3-slow

Also, without this, this failed because somehow, something is not
finding requirements-test.txt.

```
Could not open requirements file: [Errno 2] No such file or directory:
' requirements-test.txt'
```

related to T1261