Integrations are re-built on operator upgrade

[astefanutti]

Integrations are automatically rebuilt as soon as an operator pod, running version of the operator different those of the Integrations, is elected leader and takes control over these resources.

In order to avoid potential errors, caused by an unsolicited upgrade of the Integration resources, their versions should be left unchecked, and only changed by an operation explicitly triggered by users, e.g., kamel rebuild.

Note that this also affects the IntegrationKits.