TBD DefaultGeneratorManager and PropertyResolution

[manusa]

Description

WIP

The recent changes from #3042 and #296, allow to override ImageConfiguration and its BuildConfiguration (and other nested configs) settings by using properties.

However, at the moment, this will only work for projects that have a configured image (i.e. this won't work for generated container images).

We might want to change the structure of the DefaultGeneratorManager:generateAndMerge method so that resolution of properties is performed as the last step.

From the user's perspective this means that settings can be overridden with (common) properties.

Technically, this means that we don't need to duplicate properties or resolve them twice. At the moment, we are using Generator properties and configs (see BaseGenerator).