Enhance LFTP Connection Handling for test connection

[nicolemah99]

Issue Summary: Improve the robustness and clarity of the FTP connection handling in test_meter_connection.sh to address issues with incorrect or unstable IP addresses.

Proposed Changes:

1. Validate IP Address Format:
   • Ensure the provided meter_ip is in a valid IPv4 format before attempting a connection.
     2. Implement Retry Mechanism:
   • Add a retry mechanism to attempt connecting to the meter up to 3 times, with a 5-second delay between attempts.
     3. Set Connection Timeout:
   • Use a 10-second timeout for each lftp command to prevent hanging indefinitely on connection attempts.
     4. Detailed Logging:
   • Enhance logging to provide detailed output for each connection attempt, including lftp errors for diagnostic purposes.
     5. Graceful Failure Handling:
   • If all connection attempts fail, log a detailed error and exit using the fail function with EXIT_LFTP_FAIL code.

Benefits:

• Increases resilience to transient network issues.
• Provides clear diagnostics and error messages.
• Prevents the script from hanging indefinitely.
• Catches and reports invalid IP addresses early.

Tasks:

• [ ] Implement the changes in the script.
• [ ] Test with various IP addresses to ensure robustness.
• [ ] Update documentation to reflect new connection handling behavior.