Create a dynamic repository

[fvanderflier]

We should create a repository implementation that will be generic and that can accept includes data.

Acceptance Criteria

• Repository is generic
• Repository methods for getting data accepts an string[] includes argument that will build the query to the DbContext
• Repository is used in source-generated controllers instead of direct DbContext access.
• Repository will throw a domain-specific exception if a non-existent relation is passed as an argument. Take care to map this to a BadRequest in the global exception mapping.
• The repository should take care of nested includes too.