Add SSO integration and/or TLS to Uptime Kuma instance

[lvps]

Both are nearly impossible to achieve, but we can try

• SSO
• TLS

[lvps]

SSO seems feasible by disabling authentication completely and placing a (reverse) proxy in front, e.g. https://github.com/oauth2-proxy/oauth2-proxy
Only the Sysadmin group needs access and Keycloak can already provide groups, so it shouldn't be too complicated.

TLS requires port 80 or 443 accessible from the public internet (impossible) or a custom DNS installed somewhere (impossible since the port is probably firewalled) or some "fun" workaround like changing the DNS entry via OVH APIs before and after renewal