Updated OCPP 1.6 examples

Breaking changes

• Renamed profile handlers in 1.6
• Changed file and folder structure of examples

Additions & Improvements

• Added example routine for central system
• Added basic configuration support to example charge point
• Added docker-compose.tls for easy TLS testing
• Added create-test-certificates.sh utility script
• Using alpine base image for examples
• Added godoc, coverage and test report badges
• Update README and example documentation

Bugfixes

• Pending requests are now deleted automatically on disconnect