New run.sh, README.md and dockerfile optimizations

[azapater]

• Removed files pull_run.sh, pull_run_production.sh and run_production.sh
• Multiple arguments to execute run.sh with default values defined (execute run.sh -h for help)
• Dockerfile variables for PA_SERVER_URL and PA_SERVER_VERSION
• The build.sh created the image with default securepass password while the ARG was defaulted to securepass
• Dockerfile optimizations for a smaller size and better stagging/caching approach
• Fully rewritten README.md
• Updated logos
• New build.sh script for better maintainability and tagging
• Clean up on scripts for readability