Migrate protobuf definitions to pull from hedera-services repo

[RickyLB]

Problem

We need to migrate the protobuf definitions from the hedera-protobufs repository to pull from the hedera-services repository. This change is aimed at simplifying the development process and centralizing all Protobuf-related files directly within the hedera-services repo, ensuring they stay in sync with service code.

Solution

Modify .gitmodules to pull submodules from the protobuf directory in the hedera-services repo.

Alternatives

No response