Improve .env file handling and variable replacement in deployment

Major improvements to environment variable management:

1. Added .env.example files for ALL stacks
   - Each stack now has its own .env.example with only required variables
   - Variables include comments explaining their purpose
   - Examples: core, dockge, infrastructure, dashboards, arcane, media, media-management, transcoders, monitoring, sablier, utilities, productivity, wikis, vpn, homeassistant, alternatives

2. Created .env.global generation
   - Generates /opt/stacks/.env.global with all variables
   - Strips comments and blank lines for clean output
   - Available to all stacks for reference

3. Improved variable replacement strategy
   - Variable replacement now ONLY targets labels and x-dockge sections in docker-compose files
   - Configuration files (traefik, authelia) still get full variable replacement
   - Uses Python script for precise section detection
   - Preserves environment variables and volume mounts as-is

4. New deployment approach
   - Each stack copies .env.example to .env
   - Values populated from main ~/EZ-Homelab/.env file
   - No more manual sed commands to remove unused variables
   - Consistent approach across all deployment functions

5. Updated deployment functions
   - deploy_dockge, deploy_core, deploy_infrastructure, deploy_dashboards, deploy_arcane, deploy_sablier_stack
   - All now use process_stack_env() for clean .env handling
   - All use updated localize_yml_file() for targeted variable replacement

Benefits:
- Clean, minimal .env files for each stack
- No unnecessary variables or comments in deployed .env files
- Variables in compose files preserved for Docker Compose to handle
- Easier to understand what each stack needs
- Uniform deployment approach across all stacks

docker-compose/monitoring/.env.example

@@ -0,0 +1,13 @@
+# Monitoring Stack Environment Variables
+# These variables are used for Prometheus, Grafana, Uptime Kuma, etc.
+
+# Base Configuration
+DOMAIN=example.duckdns.org
+SERVER_HOSTNAME=myserver
+TZ=America/New_York
+
+# Grafana Configuration
+GRAFANA_ADMIN_PASSWORD=changeme
+
+# Directory Configuration
+STACKS_DIR=/opt/stacks