[tc][mistral][release] Propose to deprecate Mistral

Hi,

Mistral projects are unfortunately not actively maintained and caused hard times in latest official series releases for release management team. Thus we discussed this and decided to propose to deprecate Mistral [1] to avoid broken releases and last minute debugging of gate issues (which usually fall to release management team), and remove mistral projects from 2023.1 Antelope release [2].

We would like to ask @TC to evaluate the situation and review our patches (deprecation [1] + removal from the official release [2]).

Thanks in advance,

Előd Illés irc: elodilles @ #openstack-release

[1] https://review.opendev.org/c/openstack/governance/+/866562 [2] https://review.opendev.org/c/openstack/releases/+/865577