CAR Caching proxies for upstream dependent artefacts for apt packages

In order to have a reliable, secured supply chain any artefact required by SKAO should be hosted within SKAO where we can access it safely, quickly and maintain its lifecycle. To achieve this we need to host both our own artefacts and any upstream artefacts we depend on. This is also in line with 7 R's of a supply chain (in the logistics world: Getting the Right product, in the Right quantity, in the Right condition, at the Right place, at the Right time, to the Right customer, at the Right price).

To achieve a complete supply chain, it's important we first start with CAR as a first step and trickle down to each location as proxies and caches.

• Following types of upstream artefacts are cached in CAR by setting up proxies: apt
  • Seperate Debian Proxy packages into separate Nexus instances (behind apt.artefact.skao.int or something similar)
• Binary packages used in ansible-collections are investigated and changed with in the order of availability: OCI images, apt packages, binary raw artefacts
• CAR and proxies is connected with the appliances. i.e. 
  • playbooks are updated to use CAR as a proxy 
  • Servers are redeployed with the above config

A new role is added for apt package configuration: https://gitlab.com/ska-telescope/sdi/ska-ser-ansible-collections/-/merge_requests/62

This has been tested manually one of the k8s workers and update rolled out the rest of the machines, we haven't updated ubuntu20.04 machines as they will be replaced anyway and playbooks don't support any other version