fetch service_instance is not conclusive

[seilc1]

Problem

Fetching a deleted service_instance does still return the informations about the service_instance. This is a nice feature, as this allows to still show informations about a 'deleted' service_instance. The bad part is, that it's now not clear if the service_instance actually still exists.

SPEC: is not completely conclusive - 404 is only mentioned for when not existing or in creation ... not what shouls happen on deleted

Solution 1: Return 404 as soon as the service_instance is deleted

Solution 2: Add 4 new properties to the FETCH Response:

• created_at: date
• created: true
• deleted_at: null
• deleted: false

Solution 3: Retunr 410 GONE - Would not be complient with SPEC