Consolidate sample projects with Lerna

As we get more "sub-projects" in the repo—predominantly represented as separate SFDX projects for each set of samples—it would be good to properly configure a top-level project in the hierarchical structure, to allow for consistent application of project maintenance features like linting, formatting standards, etc.

We should:

1. Design a hierarchical project structure, that allows common / collective tasks to be pulled out to top-level project workflows.
2. Leverage [Lerna](https://lerna.js.org/) to stitch the hierarchy together, updating all top-level and sub-project configurations as necessary to support this configuration.

Start by mapping the separate SFDX sample projects and their current configuration files, then read the repository structure and Lerna documentation. Define a top-level hierarchy and identify which common maintenance tasks should move into top-level workflows. Done means the hierarchy and Lerna configuration consistently support linting, formatting, and related maintenance across all projects.

Written by the indexing model from the issue text.