Refactor endpoint package to provide required functions and to improve overall architecture.
Adopt refactoring in all protocol handlers (startup and shutdown behavior is changed now).
- merge packages to get a more concise layout because plugins are no more and therefore there's not a lot to be exported
- fix test logger
- rework config parsing to be easier and more transparent
- remove unnecessary APIs because dynamic endpoint handling is rather a won't implement
- introduce CLI binary
- move server binary to subdirectory to have a uniformed directory structure
- update goreleaser to build all binaries and create dist packages
- update ignore files accordingly
* 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
