Link apps together based on parent/child relationship

### Description

Some apps, like "Konkursbo" and "Oppgjør etter dødsfall", are broken into multiple apps in a parent/child relationship. Examples of this can be found in "Konkursbo" from Brønnøysundregistrene and "Oppgjør etter dødsfall" from Digdir. This relationship however are not defined up front, but is only done through regular http links from one app to the other.

In some cases the child apps can stand on their own and don't need the parent to be used, in other cases they don't make sence to be used as a stand alone app. In the latter case it makes sence to know the relationship and provide this information in service catalouges so that access to the app can be controlled through the parrent app alone and not used directly.

In "Konkursbo" there is alos the need to delegate access to all apps included in the parent/child relationship, or the logical "Konkursbo" app as a whole. In order to do this the releationship needs to be defined and known in a structured maner.

### Additional Information

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### Tasks

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### Acceptance Criterias

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No files, tests, or entry points are identified in the issue. First clarify the structured parent/child relationship and how it should support service-catalogue access control and delegation; done means the relationship and whole-app access behavior are defined for the described cases.

Written by the indexing model from the issue text.