Rpc client u subscription

[MaximilianToe]

This pull request provides the following:

• An interface for a USubscriptionClient in USubscription.h
• An Implementation of that interface in RpcClientUSubscription.cpp/RpcClientUSubscription.h
• A template method InvokeProtoMethod to send and receive requests with a specific payload type in RpcClient.h similar to the one present in up-rust
• A helper request builder and uuri builder
• Extracting part of Consumer.cpp that was also needed for USubscription to avoid code duplication

[github-actions]

Code coverage report is ready! 📈

• Code Coverage Percentage: 90.60%
• Code Coverage Report: View Coverage Report

[PLeVasseur]

Hey @MaximilianToe -- thanks for contributing!

I noted more up-spec-related items and have tagged @sophokles73 and @stevenhartley onto the PR as there may be gaps in the spec (or in my understanding of it!)

[github-actions]

Code coverage report is ready! 📈

• Code Coverage Percentage: 90.50%
• Code Coverage Report: View Coverage Report

[sophokles73]

@PLeVasseur would you mind taking another look?

[PLeVasseur]

Yup, will do. Try to make it fit this week 👍

[PLeVasseur]

Thank you for the updates @MaximilianToe! Can you take a look at the comments I left?

It feels to me there's still a bit of alignment work to ensure that the C++ RpcClient API mimics the Rust equivalent. Happy to hear your thoughts.

[github-actions]

Code coverage report is ready! 📈

• Code Coverage Percentage: 90.50%
• Code Coverage Report: View Coverage Report