Some teams are expecting `cacert` to always be present in the kafka broker config – some are not. Some are expecting a `nil`/`null` value for it, some are expecting the key to be absent, etc. etc.

In theory, we should not need a ca cert because the managed kafka cert is signed by a well-known certificate authority.

But, as a short term solution (since different apps/libraries are handling the abscence of the key differently), we are going to have clowder provide the `cacert` in the cdappconfig.json.

I am adding the DigiCert High Assurance EV Root CA to the 'clowder-oauth' vault secret used in stage – then updating clowder to parse the cacert out of this secret and insert it into cdappconfig.json