- use `Unmarshal` method of viper
- move config loading, defaulting and stuff to config package
- move serve to an extra command and move keep only global flags in root command
- add startup logic to onInit method in root command
- update mocks
- clean config structs
- adopt changes in plugins
- update default config
- introduce new endpoints module
- introduce Endpoint and EndpointManager
- introduce new Logging abstraction API to allow proper mocking
- add error return value to Start and Shutdown of endpoints
- add mocks of some internals to allow easier testing
- add generate target to take care of all code generation
* supports HTTP
* support TLS interception e.g. for HTTPS
* support CA generation via cli
* first draft of plugin API
* support commands from plugins
* includes Dockerfile
* includes basic configuration
