feat: Add Option 3 - Deploy Additional Server with multi-server support

Major features:
- Automated SSH key setup between remote and core servers
- Docker TLS configuration with shared CA certificates
- Automatic deployment of Dockge, Traefik, Sablier, and Infrastructure stacks
- Copy all stacks (except core) to remote server for on-demand deployment
- New standalone Traefik stack for remote server container discovery
- Locale-aware SSH/SCP commands to handle Raspberry Pi warnings
- Variable expansion support in .env files (${VAR} references)
- Comprehensive error handling and verbose deployment logging

Technical improvements:
- setup_ssh_key_to_core() - Automated RSA 4096-bit key generation and installation
- setup_multi_server_tls() - Fetch shared CA from core server via SSH
- copy_all_stacks_for_remote() - Deploy all stacks except core
- deploy_traefik_stack() - Local Traefik for container discovery
- Enhanced localization with envsubst support
- Docker network creation (traefik-network, homelab-network)
- Password authentication with special character handling

Fixes:
- Fixed SSH key path handling for non-root users
- Fixed SCP exit code checking (was checking grep instead of scp)
- Fixed CA file detection with proper test commands
- Removed unnecessary prepare_deployment() function call
- Added ACTUAL_USER variable initialization for remote deployments

.env.example

@@ -10,14 +10,7 @@ TZ=America/New_York
 
 # Servers configuration
 SERVER_IP=192.168.1.100     # This server                         
-SERVER_HOSTNAME=debian                          
-
-# If deploying with option 3: Remote Core Server
-# the REMOTE_SERVER is where the Core Stack (Traefik) is running
-REMOTE_SERVER_IP=your.remote.ip.address         
-REMOTE_SERVER_HOSTNAME=your-remote-server 
-REMOTE_SERVER_USER=${DEFAULT_USER}  
-REMOTE_SERVER_PASSWORD=${DEFAULT_PASSWORD}  
+SERVER_HOSTNAME=debian                           
 
 # Domain Configuration
 DUCKDNS_SUBDOMAINS=yourdomain    # Without .duckdns.org
@@ -35,6 +28,13 @@ MEDIADIR=/mnt/media           # Large media files on separate drive
 DOWNLOADDIR=/mnt/downloads    # Downloads on separate drive
 PROJECTDIR=~/projects         # User's projects folder
 
+# If selecting option 3: Deploy Additional Server
+# the CORE_SERVER is where the Core Traefik is running
+CORE_SERVER_IP=192.168.1.101
+CORE_SERVER_HOSTNAME=debian2
+CORE_SERVER_USER=${DEFAULT_USER}
+CORE_SERVER_PASSWORD=${DEFAULT_PASSWORD}
+
 # ##########################################
 # #### NOTEABLE OPTIONAL CONFIGURATIONS ####