helm chart: Allow skipping creation of secret for api_key

[sroman-gfm]

Hello!

Would it be possible to modify the helm chart for pdp so that it allows users to mount the secret as an env var with a tool like https://bank-vaults.dev/? Currently I see no way to skip creating the k8s secret for the api key and then mounting it as an env var.

To be specific, I'd like to be able to set a value like userProvidedSecret: true and that would disable creation of the k8s secret and also would not try to mount it as an env var in the pdp container, thus delegating to the user passing a valid pdp api key via the PDP_API_KEY env var with the pdpEnvs value.

If you are open to me opening a pull request for this I wouldn't mind doing so.

Thank you.