[Feature Request] Optional build acceleration

**Is your feature request related to a problem? Please describe.**
Builds, especially from scratch, can take a long time (+1 hour). One way to mitigate this is to run builds across multiple cores / build tasks, as is documented in the [O3DE build documentation](https://www.o3de.org/docs/user-guide/build/configure-and-build/#build-a-project) ([`-- -m`](https://learn.microsoft.com/en-us/visualstudio/msbuild/building-multiple-projects-in-parallel-with-msbuild?view=vs-2022) flag for Windows, `-j ...` for Linux)

**Describe the solution you'd like**
Enable optional build acceleration for users running on compatible machines.

The issue names no repository files, tests, or entry points. Start by locating how this sample invokes O3DE builds, then compare the documented Windows -- -m and Linux -j options. Done means users on compatible machines can optionally enable parallel builds without changing the default behavior.

Written by the indexing model from the issue text.