Read license from file in tunnel client deployment vs from argument

Read license from file in tunnel client deployment vs from argument

## Expected Behaviour

I would like the secret to be read from a file i.e. a Kubernetes secret which is mounted, so that the secret can be updated without editing the deployments

## Current Behaviour

If the license needs to be rotated, we have to edit each deployment in Kubernetes, or delete the deployment and have it recreated. The license also "leaks" via `kubectl get deployment`

## Possible Solution

Create a secret for the inlets-pro license when deploying the operator, then bind this to each deployment. It may also be necessary to re-create the secret in each namespace where it is used by a tunnel deployment. I'm not sure that there's a way around this.