Refactor: generation logic / add gateway

Refactor: generation logic / add gateway

• Add new alpha gateway functionality
• Refactor folder structure
• Refactor Makefiles
• change generation logic
• add more generation options. Instead of using the proto plugin you have the option to generate graphql using a special binary
• get rid of gogqlcfg now there is no reason to use it with gqlgen autobind features
• gql plugin adds documentation to generated graphql schema from protobuf comments
• better examples