Add first Knative trait and profiles

[nicolaferraro]

kamel install now understands if Knative is installed in the cluster and automatically activates the Knative profile (list of traits to be enabled) and installs additional roles and bindings for the operator.

When using the Knative profile, a Knative Service is created instead of a Deployment. Later on we will add support for other kind of resources, such as EventSources.

The bad thing about the approach is that Knative serving CRD don't support mounting volumes (including configmaps) in order to wrap all the state in a single resource.
For this reason, I push the code into an ENV variable... not pretty... but I couldn't find a better solution that didn't include building a new image...

[lburgazzoli]

can we access config maps through k8s api ?

[nicolaferraro]

Mmh, no. Each time you do a deployment in Knative, you add a revision ad it should be self contained because you're able to change Istio routes to load-balance old revisions too.

If we keep the configmap separated, no matter the technology you use to load it, you're flattening all revisions to latest version.

So, I think the way to go is to make some changes in Knative serving to add better support for "configuration files".