Related to T4105

This nests the historical roadmap under a specific roadmap/index
toctree, so that they don't all show up in the sidebar.

This fixes the build [1]

[1] https://jenkins.softwareheritage.org/job/DDOC/job/dev/1139/console

[1] https://jenkins.softwareheritage.org/job/DDOC/job/dev/1135/console

Without this, the actual documentation build will fail once a new package is
incompletely installed.

Do not generate TOC with sphinx-apidoc.

Mark the apidoc/swh.rst file as orphan.

To install the new hook:

  $ pre-commit install -t commit-msg

Related to T3907

To avoid discrepancy with tox when pre-commit is triggered.

Related to T3829

use proper `:file:`, `:command:` and `:envvar:` roles.

using `docker service update --config-add` like commands.

with infrastructure sizing estimations.

and merge duplicate parts

Related to T3829

This fixes warning like [1] and attempt to fix the build [2]

[1]
```
16:47:16  /var/lib/jenkins/workspace/DDOC/build-on-diff/swh-docs/user/faq/index.rst:41: WARNING: hardcoded link 'https://archive.softwareheritage.org/save/' could be replaced by an extlink (try using ':swh_web:`save/`' instead)
```

[2] https://jenkins.softwareheritage.org/job/DDOC/job/build-on-diff/59/console

we will need to fix this later on.

It's mandatory to use :swh_web: instead of archive.s.o since
sphinx 4.4.0

It's mandatory to use :swh_web: instead of archive.s.o since
sphinx 4.4.0