Postgres/Mysql/Redis analyzers should support a valueFrom for URI

[marccampbell]

Currently, the only way to pass the URI to one of the database analyzers is to hard code it and write it into a spec. Often this is handled via templating to make it portable.

The uri field should support referencing an existing secret also, much like env vars do. Ideally, we can just reuse existing K8s objects and make it a struct, like:

uri:
  value: <>
  valueFrom:
    secretKeyRef:
     ...

[xavpaice]

@marccampbell is this issue still current? Could use a bit more detail.