It's an associated requirement with Upstream Authority feature (SPIRE-129)

This would be an important function for admin to configure when managing CA hierarchy and rotation.

Currently the SPIRE Server uses a hardcoded CA TTL value as 24h: https://github.com/openshift/zero-trust-workload-identity-manager/blob/dfcaa616ce964ac292b3109c9ed9d41603e9ffea/pkg/controller/spire-server/configmap.go#L145

Additionally we also need to evaluate if `default_jwt_svid_ttl` and `default_x509_svid_ttl` should support customized in this time. https://github.com/openshift/zero-trust-workload-identity-manager/blob/dfcaa616ce964ac292b3109c9ed9d41603e9ffea/pkg/controller/spire-server/configmap.go#L147-L148