Remove entityVersion from public APIs

[snazy]

Describe the bug

polaris-management-service.yml uses a simple entityVersion approach to validate whether some update request, which includes the full representation of the entity to be updated, can be performed or not.

The approach to be able to update a whole entity should be replaced with specific update operations per entity type. This is much easier to validate in service implementations and easier to understand from a client's point of view.