chore: update deployment script

[MexicanAce]

Description

• Update the deployment scripts to remove the requirement of passing in a Private Key via command line parameters
• Added example .env file
• Allow funding of the paymaster when its deploying on its own
• Update the error messages upon certain failures

Additional context

The use of private keys in command line parameters is a security risk because the PK is then stored in your shell's history and also readable if you're sharing your screen. Moving to to a .env file will help alleviate this.