This fixes python 3.7 support due to poetry, a dependency of isort, that
removed support for that Python version in a recent release.

In order to remove warnings about /apidoc/*.rst files being included
multiple times in toc when building full swh documentation, prefer to
include module indices only when building standalone package documentation.

Also include them the proper sphinx way.

Related to T4496

- 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being outdated).

The command will help people to setup their authentication token.

There are more manual step than we would like, but this pave the way to
even more automated method.

This should make the problem more obvious to new users.

This should help use to validate the rate limit approach and understand
the inconsistency in what the server is sending us.

We retry on error and we adjust to the `X-RateLimit` header the server
send us. This is quite basic, and has to struggle against the async
implementation of the request.

So further works should probably refactor the concurrency of the request
implementation before going further.

See inline documentation for details.

Better handling of ClientConnectionError are also needed.

This make the user function simpler.

This simplify the function we call in the loop, cannot hurt.

This has not reason to be a closure, so let it not be a closure.

Let us put the simple case first and the longer one after it.

This have no reason to be a closure, so we extract it as a proper
function.

This is a first batch of things (VCS and tools) we know that we don't
want to scan. The list will likely extend in the future and we should
also apply DVCS's ignore request too.

This should be less scary than "text" for a first contact.

This is a small and minimal output to display some information without
overwhelming the user with a wall of text.

Example output:

```
Files:                     89
            known:         40   ( 44%)
directories:               11
      fully-known:          3   ( 27%)
  partially-known:          0   (  0%)
```

It can most probably be improved, but this can come later.

This is still quite short, but already better. This leave room for
expanding the format list and the associated description.

This seems like a good default and smooth the first contact with the
tool.

That hook can be frustrating as it can discard a long commit message
if it finds a typo in it so better removing it.

Related to T3922

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

pytest-postgresql 3.1.3 and pytest-redis 2.4.0 added support for
pytest >= 7 so we can now drop the pytest pinning.

Due to test modules being copied in subdirectories of the
build directory by setuptools, it makes pytest fail by raising
ImportPathMismatchError exceptions when invoked from root
directory of the module.

So ignore the build folder to discover tests.

To install the new hook:

  $ pre-commit install -t commit-msg

Related to T3916

This also drops spurious copyright headers to those files if present.

Related to T3812

- additional information about software artifacts can be specified
using the CLI with the -e/--extra-info option
- add support to retrieve origin information using swh-graph
- move backend requests to a separate submodule (client)

- query all nodes if they fill the backend size limit
- docstring for the various policies

- make scan policy selectable through --policy/-p option
- abstract 'Policy' class to create new scan policies
- integration of existing policies into the master branch

Closes T3420

Closes T3349
Closes T2730
Closes T2692