feat: add cmake example

[ciband]

Proposed changes

Added a standalone example for how to use cpp-client. Top level example directory can be pulled out of the cpp-client source tree and be used as a started point for a new project.

Types of changes

• Bugfix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Refactoring (improve a current implementation without adding a new feature or fixing a bug)
• Breaking change (fix or feature that would cause existing functionality to not work as expected)
• Build (changes that affect the build system)
• Docs (documentation only changes)
• Test (adding missing tests or fixing existing tests)
• Other... Please describe:

Checklist

• I have read the CONTRIBUTING documentation
• Lint and unit tests pass locally with my changes
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation (if appropriate)

Further comments

N/A

[sleepdefic1t]

This PR was updated to remove the Arduino support fix, as it will be resolved in a later PR.

Everything else looks good 👍

[sleepdefic1t]

Mac test issue discussed at ArkEcosystem/Cpp-Crypto Issue #27.

This can now be merged @faustbrian