Add Bitwarden, setup script, remove redundant files, update disk requirements, and add LinuxServer preference

- Add Vaultwarden (Bitwarden) password manager to utilities.yml
  - Self-hosted password manager with web UI
  - SMTP configuration for email notifications
  - Admin token for management
  - Access at bitwarden.${DOMAIN}
  - Protected by Authelia SSO

- Create automated first-run setup script (scripts/setup-homelab.sh)
  - Installs Docker Engine and Compose V2
  - Configures user groups (sudo, docker)
  - Enables SSH for remote management
  - Detects NVIDIA GPU and provides manual driver installation instructions
  - Creates directory structure and Docker networks
  - Comprehensive instructions for post-setup deployment

- Remove redundant compose files (now in core.yml)
  - Deleted authelia.yml, duckdns.yml, gluetun.yml, traefik.yml
  - All services consolidated into unified core.yml stack
  - Eliminates confusion and duplication

- Update disk space requirements across documentation
  - Changed from "100GB+ system, 1TB+ media" to:
  - "120GB+ system drive (NVMe or SSD highly recommended)"
  - "2TB+ for media & additional disks for services like Nextcloud"
  - Updated in README.md and getting-started.md

- Add preference for LinuxServer.io images
  - Updated copilot-instructions.md
  - LinuxServer images support PUID/PGID for proper file permissions
  - Preference noted in consistency guidelines

- Update core stack documentation
  - Emphasize unified core.yml deployment
  - Add both deployment methods (cd to directory vs full path)
  - Update getting-started.md with correct deployment steps
  - Note removal of separate stack files

- Add Bitwarden environment variables to .env.example
  - BITWARDEN_ADMIN_TOKEN, SIGNUPS_ALLOWED, INVITATIONS_ALLOWED
  - SMTP configuration for email notifications
  - Generation instructions included

- Update services-reference.md
  - Add Vaultwarden to utilities section (now 7 services)
  - Update service count and access URLs

All documentation now consistent with unified core stack approach and includes all requested features.

Co-authored-by: kelinfoxy <67766943+kelinfoxy@users.noreply.github.com>

docs/services-reference.md

@@ -67,7 +67,8 @@ This document provides a comprehensive overview of all 60+ pre-configured servic
 | │  └─ mediawiki-db | MariaDB | - | /opt/stacks/productivity | No UI |
 | └─ Form.io | Form builder | ✓ | /opt/stacks/productivity | forms.${DOMAIN} |
 |    └─ formio-mongo | MongoDB | - | /opt/stacks/productivity | No UI |
-| **🛠️ utilities** (6) | | | | |
+| **🛠️ utilities** (7) | | | | |
+| ├─ Vaultwarden | Password manager | ✓ | /opt/stacks/utilities | bitwarden.${DOMAIN} |
 | ├─ Backrest | Backup (restic) | ✓ | /opt/stacks/utilities, /mnt/backups | backrest.${DOMAIN} |
 | ├─ Duplicati | Encrypted backups | ✓ | /opt/stacks/utilities, /mnt/backups | duplicati.${DOMAIN} |
 | ├─ Code Server | VS Code in browser | ✓ | /opt/stacks/utilities | code.${DOMAIN} |