Restructure project

We previously didn't really had any structure in our project apart
from creating a new folder for each package in our project root.
Now that we have accumulated some packages, we use the well-known
Golang project layout in order to clearly communicate our intent
with packages. See https://github.com/golang-standards/project-layout

internal/api/websocket_connection_mock.go

@@ -0,0 +1,93 @@
+// Code generated by mockery v0.0.0-dev. DO NOT EDIT.
+
+package api
+
+import (
+	io "io"
+
+	mock "github.com/stretchr/testify/mock"
+)
+
+// webSocketConnectionMock is an autogenerated mock type for the webSocketConnection type
+type webSocketConnectionMock struct {
+	mock.Mock
+}
+
+// Close provides a mock function with given fields:
+func (_m *webSocketConnectionMock) Close() error {
+	ret := _m.Called()
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func() error); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}
+
+// CloseHandler provides a mock function with given fields:
+func (_m *webSocketConnectionMock) CloseHandler() func(int, string) error {
+	ret := _m.Called()
+
+	var r0 func(int, string) error
+	if rf, ok := ret.Get(0).(func() func(int, string) error); ok {
+		r0 = rf()
+	} else {
+		if ret.Get(0) != nil {
+			r0 = ret.Get(0).(func(int, string) error)
+		}
+	}
+
+	return r0
+}
+
+// NextReader provides a mock function with given fields:
+func (_m *webSocketConnectionMock) NextReader() (int, io.Reader, error) {
+	ret := _m.Called()
+
+	var r0 int
+	if rf, ok := ret.Get(0).(func() int); ok {
+		r0 = rf()
+	} else {
+		r0 = ret.Get(0).(int)
+	}
+
+	var r1 io.Reader
+	if rf, ok := ret.Get(1).(func() io.Reader); ok {
+		r1 = rf()
+	} else {
+		if ret.Get(1) != nil {
+			r1 = ret.Get(1).(io.Reader)
+		}
+	}
+
+	var r2 error
+	if rf, ok := ret.Get(2).(func() error); ok {
+		r2 = rf()
+	} else {
+		r2 = ret.Error(2)
+	}
+
+	return r0, r1, r2
+}
+
+// SetCloseHandler provides a mock function with given fields: h
+func (_m *webSocketConnectionMock) SetCloseHandler(h func(int, string) error) {
+	_m.Called(h)
+}
+
+// WriteMessage provides a mock function with given fields: messageType, data
+func (_m *webSocketConnectionMock) WriteMessage(messageType int, data []byte) error {
+	ret := _m.Called(messageType, data)
+
+	var r0 error
+	if rf, ok := ret.Get(0).(func(int, []byte) error); ok {
+		r0 = rf(messageType, data)
+	} else {
+		r0 = ret.Error(0)
+	}
+
+	return r0
+}