switch to Fabric v3

[adecaro]

Currently, we import code from Fabric v2.5 and its protos. This keeps us bound to deprecated dependencies, like proto marshaller. This Github issue asks to upgrade the Fabric dependency to v3, including the protos.
In addition, all the packages moved to fabric-lib-go should be used.

We must make sure we can still compile the token-chaincode for fabric v2.5.

This EPIC is born from the need of merging #731 that introduces new features in Idemix that the token-sdk needs to leverage. Unfortunately, #731 requires the new fabric protobuf messages.