Implement C++ SDK

[hubcio]

Currently, we have non-working skeleton of C++ SDK in foreign/cpp directory. The aim of this task is to write minimal C++ SDK which will allow users to send and poll.

Preferably, we want to call Rust via FFI. See python SDK in foreign/pyton, where we use pyo3 for Rust<->Python interop.

For building the project, see #1774, we want to use bazel.

[jaroslawroszyk]

Please assign me @hubcio

[hubcio]

@jaroslawroszyk any progress? you need some help?

[chiradip]

@jaroslawroszyk - let me know if you need help

[jaroslawroszyk]

@chiradip I started working and understood the requirements from Hubert

[dyumin]

For building the project, see #1774, we want to use bazel.

Please, don't

[slbotbm]

@hubcio please assign this issue to me

[slbotbm]

@hubcio @spetz

I've made the following plan to get split the current PR into 3 parts as described in the discord message.

1. The build system + the scripts: Implement the CI building and testing infrastructure + Bazel + CMake build scripts. This will also include CompressionAlgorithm, Expiry, MaxTopicSize, and PollingStrategy, which are convenience classes we provide to the user and do not have any relation to the generation of the FFI bindings.These will be tested with simple unit tests to prove that the CI works.
2. The rust side FFI bindings: this will produce the low-level client. Unit and integration tests will also be included.
3. The high-level C++ client: This will wrap the low-level client in more convenient classes and make it easier to work. Unit and integration tests will also be included.