Build from git: decouple Build from Integration

[squakez]

Requirement

We need to revisit how the Build custom resource is managed by the Integration. Right now, the Build is created into the same namespace where the Integration exists. This is good for garbage collection as we can related the Build with the Integration. However, this requires the operator to manage RBAC directly as it must create a SA when running with builder pod strategy (which may become the only strategy in the future).

We can change this approach and let instead the Build to be created in the operator namespace: it won't require any special SA, as it already exists in the operator NS. However it won't allow the automatic garbage collection as the Integration won't be able to control another namespace object.

Also the builder Pod would happen either in the user namespace or the operator namespace. We need to analyze in deep the pros and cons of each approach and come out with a final design.