Support issue of CA certificates using VaultPKICert

[dm3ch]

Is your feature request related to a problem? Please describe.
I would like to see a support of issuing CA certificates using VaultPKISecret.

Describe the solution you'd like
I want to be able to issue VaultPKISecret managed CA cert. For example it would be useful for creation of istio-system/cacerts mesh cluster CA cert

Describe alternatives you've considered

• Support cross-signed intermediate CAs issued with Vault cert-manager/cert-manager#7645

Additional context
Add any other context or screenshots about the feature request here.