Capabilities vocabulary: Add EntityContainer as annotation target

[ralfhandl]

If a service that exposes multiple entity sets as endpoints implements only the minimal conformance level and wants to inform clients about its (in)capabilities, it is required to annotate each entity set individually with the restriction terms (top&skip&compute supported, filter & sort restrictions, change tracking etc. These are many repetitions just to express restrictions at service level.

Proposal

• Create new term at container level with all settings from existing terms that are not yet applicable to containers and do not reference individual properties:

• Refactor the existing complex types used by the existing terms to be derived from base types used for the properties of the new container-level term.
• State for each capability that it is combined with the container-level defaults using PATCH semantics, i.e. all container-level default values that are not explicitly changed in a set-level annotation still apply.

Imported from ODATA-1412