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/environment/manager_mock.go

@@ -0,0 +1,55 @@
+// Code generated by mockery v2.8.0. DO NOT EDIT.
+
+package environment
+
+import (
+	mock "github.com/stretchr/testify/mock"
+	dto "gitlab.hpi.de/codeocean/codemoon/poseidon/pkg/dto"
+
+	runner "gitlab.hpi.de/codeocean/codemoon/poseidon/internal/runner"
+)
+
+// ManagerMock is an autogenerated mock type for the Manager type
+type ManagerMock struct {
+	mock.Mock
+}
+
+// CreateOrUpdate provides a mock function with given fields: id, request
+func (_m *ManagerMock) CreateOrUpdate(id runner.EnvironmentID, request dto.ExecutionEnvironmentRequest) (bool, error) {
+	ret := _m.Called(id, request)
+
+	var r0 bool
+	if rf, ok := ret.Get(0).(func(runner.EnvironmentID, dto.ExecutionEnvironmentRequest) bool); ok {
+		r0 = rf(id, request)
+	} else {
+		r0 = ret.Get(0).(bool)
+	}
+
+	var r1 error
+	if rf, ok := ret.Get(1).(func(runner.EnvironmentID, dto.ExecutionEnvironmentRequest) error); ok {
+		r1 = rf(id, request)
+	} else {
+		r1 = ret.Error(1)
+	}
+
+	return r0, r1
+}
+
+// Delete provides a mock function with given fields: id
+func (_m *ManagerMock) Delete(id string) {
+	_m.Called(id)
+}
+
+// Load provides a mock function with given fields:
+func (_m *ManagerMock) Load() 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
+}