chore: all sub-repos CONTRIBUTING.md — add independent operation section

[kristopherjturner]

Summary

Every sub-repository's CONTRIBUTING.md should describe how to use and work with the repo independently, outside the multi-repo workspace. This allows contributors to open just one repo and have a productive development setup without needing the parent workspace.

Requirements

Each CONTRIBUTING.md should include a section covering:

Independent Operation

## Working Independently

This repository can be used as a standalone project without the parent multi-root workspace.

### Open Only This Repository

1. Open VS Code
2. File > Open Workspace from File > select `azurelocal-{product}.code-workspace`
3. All recommended extensions will be prompted for installation

### Prerequisites

- Python 3.x and pip (for MkDocs documentation)
- [MkDocs Material](https://squidfunk.github.io/mkdocs-material/): `pip install mkdocs-material`

### Run Documentation Locally

```bash
mkdocs serve

Browse to http://127.0.0.1:8000

Build Documentation

mkdocs build

## Repos Requiring This Change

- [ ] azurelocal-avd
- [ ] azurelocal-sofs-fslogix
- [ ] azurelocal-loadtools
- [ ] azurelocal-vm-conversion-toolkit
- [ ] azurelocal-nutanix-migration
- [ ] azurelocal-training
- [ ] azurelocal-copilot
- [ ] azurelocal-ranger
- [ ] azurelocal-S2DCartographer

## Acceptance Criteria

- Each `CONTRIBUTING.md` includes a section on independent workspace usage
- The section references the repo's own `.code-workspace` file by name
- Local MkDocs serve/build instructions are present

[kristopherjturner]

Completed

All sub-repos now have the ## Working Independently section in CONTRIBUTING.md:

• ✅ azurelocal-avd
• ✅ azurelocal-sofs-fslogix
• ✅ azurelocal-loadtools
• ✅ azurelocal-vm-conversion-toolkit
• ✅ azurelocal-nutanix-migration
• ✅ azurelocal-training
• ✅ azurelocal-copilot
• ✅ azurelocal-ranger (CONTRIBUTING.md created from scratch)
• ✅ azurelocal-S2DCartographer

Each section covers: opening the repo's own .code-workspace file, MkDocs prerequisites, mkdocs serve, and mkdocs build.