feat(grpc): add get assets query params filtering to grpc

[mabdh]

Is your feature request related to a problem? Please describe.
In #88, we add more filtering feature in Get Assets API. However this is only for HTTP API, we need to replicate this feature in grpc since we will deprecate HTTP API later and use grpc-gateway instead.

Describe the solution you'd like

• add exact query params filtering feature to GetAllAssets API in grpc
• the filtering in grpc-gateway should have the same behaviour with the existing one
• Update the proto here