and bump the advertised minimal python version to 3.10

Refs. swh/infra/sysadm-environment#5315

Also add a description of the hardware used by swh
to help to the decisions

Related to swh/infra/sysadm-environment#5301

Refs. swh/infra/sysadm-environment#5296

It is a dependency required to build docutils >= 0.21 that does not get
installed in the virtualenv used to build the documentation as we use the
pip option --no-build-isolation that skips installation of build dependencies
specified by PEP 518.

It is not hardcoded 5080 any more.

URL of docker environment repository has changed so update accordingly.

It is a dependency required to build psycopg-c that does not get installed
in the virtualenv used to build the documentation as we use the pip option
--no-build-isolation that skips installation of build dependencies specified
by PEP 518.

Related to swh/infra/sysadm-environment#5271

Refs. swh/devel/swh-loader-core#4749

Refs. swh-loader-core#4749

Refs. swh/infra/sysadm-environment#5251

Refs. swh/infra/sysadm-environment#5251

It fixes some warnings when building the SWH documentation.

Related to swh/infra/sysadm-environment#5239

It's been migrated to the dynamic infra.

Refs. swh/infra/sysadm-environment#5237

Related to swh/meta#5075.

Refs. swh/infra/sysadm-environment#5215