restructured examples, added cpp sdk

[DevrathIyer]

No description provided.

[ygina]

Thanks for the pull request! Two high-level comments:

1. Is it necessary to track all these files, particularly in the Python SDK? If they need to be regenerated when the Python source changes, it would be best to not track them but include instructions on how to regenerate them. If they need to be tracked because that's how the package manager works, it would still be better to include documentation on how to update and re-publish the package if necessary.
2. Regarding how the karl-sensor-sdk directory is structured, it is a bit odd that it is now the root for what seems to b a Rust project and a C++ project and maybe also a Python project. I'd expect it to look more like this:

karl-sensor-sdk/
--- rust/
--- --- src/
--- --- examples/
--- --- Cargo.toml
--- cpp/
--- --- examples/
--- --- common.cmake
--- python/

Does that make sense, or is there a reason you structured it this way? The only other type of thing I might expect in the karl-sensor-sdk directory is a script that regenerates the gRPC file each language when it is updated.