Add network message for querying asset data

[philippwerner]

Problem: asset records in universe can only be queried by user ID at the moment

Generalized query of asset records, which allows to:

• query all issued assets
• query all ownership records of a certain asset type, optionally with filtering by owner and managing contract
• query all possession records of a certain asset type, optionally with filtering by possessor and managing contract
• query by universeIdx

Applications:

• testing / debugging with qubic-cli
• rich-list, e.g. planned by QVAULT (querying and sorting to be implemented outside core by second layer)
• listing existing assets for QX frontend Add qxListAssets or similar to list all assets #109

Questions:

• Should this be added to the core as an open interface? Or should we force non-debugging applications to keep track of the universe via initial state + logging changes?
• Siblings needed?

Task: Implement in core and qubic-cli