Use C++ SDK package in the C++ quickstart example

[charlesbvll]

Issue

Description

Currently you need the local SDK files to be able to compile the quickstart-cpp example, meaning it can't be run in a standalone fashion.

Related issues/PRs

N/A

Proposal

Explanation

Use FetchContent to get the C++ SDK dependencies necessary for the quickstart-cpp example. Also provides a compile argument to use the local source instead (useful for tests) and use it in the CI workflow.

Checklist

• Implement proposed change
• Make CI checks pass
• Ping maintainers on Slack (channel #contributions)

Any other comments?

N/A