Fix proto buffer pass by value, shallow copying or unsafe comparisons

[Martin2112]

We need to update proto buffer usages where they are passed by value or compared by generic code like reflect.DeepEquals(). Passing them by value creates shallow copies that can share internal state. As the generated structs contain additional exported XXX_ fields managed by the proto implementation generic comparisons using all fields can produce incorrect results.

Typical problem cases:

• Passing a proto as a value parameter to a func
• Using a proto as a map key
• Struct assignment of a proto in cases like *proto1= proto2
• Using a proto as a value field in another struct (commonly test structs)
• Using json.Marshal, reflect.DeepEquals or similar on protos

The scope of this should be limited as we don't use protos heavily outside gRPC interfaces and storage.

[Martin2112]

Can't 100% guarantee that I've fixed all of them but I think I've got most of the ones in our repositories that can be found by go vet.