Configurable Certificate Expiry and Cert Renewal

With an old enough environment, DX's certs can expire when using cert-manager managed certificates. cert-manager automatically renews the cert but there's then a few challenges:
1. Having DX pod be aware of the renewed cert and restarting
2. Using the appropriate FF APIs to have the new DX cert be broadcasted out to everyone in the network

First step, is we could let the expiry time of the cert be configurable in case folks want their certs to last longer than the default 3 months. And then, we'll need to figure out what combination of sidecars, annotations, and Jobs need to be put in place to solve the above.

Start by locating the Helm chart values and templates for cert-manager-managed certificates and the DX pod. Trace how expiry configuration relates to the listed restart, sidecar, annotation, Job, and FF API concerns. Done requires a clear implementation path for configurable expiry and certificate renewal handling.

Written by the indexing model from the issue text.