Improve .env file handling in start script

[kshitijk4poor]

Current Behavior

The start.sh file checks for the existence of a .env file. If the file is not found, it displays a warning message and exits.

Proposed Change

Instead of just showing a warning and exiting, we should:

1. Detect if the .env file exists.
2. If it doesn't exist:
   • Display a message indicating that we're copying the .env file.
   • Copy the template env.example file to the correct location.
   • Provide a message referring users to the documentation for customization and continue.