Introduce a new subdomain dev.iscsc.fr to publish in-development features from opened PRs

[ctmbl]

EDIT: see PR has been amputated from the deployment workflow part, #61 will complement it, see #53 (comment) to fully understand

see https://dev.iscsc.fr/

• create a DNS redirection: dev IN CNAME iscsc.fr. on https://www.ovh.com/manager/#/web/zone/iscsc.fr tks to https://help.ovhcloud.com/csm/en-domain-subdomains-creation?id=kb_article_view&sysparm_article=KB0060738
• add a nginx config
• update docker compse to share appropriate volumes
• create appropriate certificates with certbot

[ctmbl]

EDIT: after #53 (comment) this comment doesn't makes sens here and will be moved in the next PR #61

To require manual approval of the deployment of a PR to dev.iscsc.fr I could have used https://github.com/marketplace/actions/manual-workflow-approval but it creates an issue every time such as liquibase/liquibase#5740 which isn't suitable in our case

I preferred to use the GitHub way with Environments and created a deployment-dev environment whihc requires my approval to allow the workflow to run:

• https://github.com/iScsc/blog.iscsc.fr/settings/environments
• https://docs.github.com/en/actions/deployment/targeting-different-environments/using-environments-for-deployment#using-an-environment
• b45155a

[ctmbl]

This PR will be amputated from the deploy-dev workflow part 😢

Because I issued this PR from my fork I can't access organization secrets from this PR and then can't test the desired behavior of the workflow I'm introducing here.
see https://github.com/iScsc/blog.iscsc.fr/actions/runs/9133155933/job/25116011582 and https://github.com/iScsc/blog.iscsc.fr/actions/runs/9133155928/job/25116011588 "Debug"
the from ctmbl:dev-subdomain is the pb!

So this PR will be restraint to the update of the nginx config, docker compose and production deployment workflow

[ctmbl]

The PR has been heavily tested manually on the server, using the README instruction thoroughly and everything went well

ready to merge ✔️ 🚀