Improve error reporting in case of knative is required but not installed

[claudio4j]

Fix #3803

The knative check, required the Client object in Environment for various tests.

Release Note

Fix: Improve error reporting in case of knative is required but not installed

[squakez]

LGTM, however I wonder if we can reduce that code duplication in the deployment and cron traits moving the logic in the container trait instead:

camel-k/pkg/trait/container.go

Line 184 in 92077dd

// Deployment

If not, please consider to create a func with the logic and call it from the 2 places instead.

[squakez]

I think it makes sense to backport this one to 1.12 and 1.10.