Server public IP validation and arguments parsing fixes

• Fix server public IP validation on platform like AWS or Google Compute Engine
• Fix arguments parsing
• Improve code quality

v2.0 Unified script

• Unified script with standalone & cloudflare acme validation available
• Unified command ee-acme to generate a certificate
• add argument parsing support
• add usage documentation available with argument --help or -h
• add verification between each steps to avoid issues
• do not reload if configuration is incorrect
• add support for Nginx Mainline release 1.15.x

First Release

This is the initial release for ee-acme-sh.