Use plural for compass API response

[mabdh]

Is your feature request related to a problem? Please describe.
In compass API, we use data field as a field that wrap results of GET API. Although the idea was to make all GET API having the same scaffolding of API response (since it will also be translated to REST response with grpc-gateway) but this might not be that flexible for future use cases. Having plural names of the type of results would make it more future-proof.

repeated Asset assets = 1;

Describe the solution you'd like
Update the response fields to use plural names instead of data