Rename execution.Storage to Storer to follow Go convention

Interfaces should be named like someone actively doing a thing. Thus,
instead of Storage we use Storer.

internal/runner/runner.go

@@ -37,7 +37,7 @@ type Runner interface {
 	// MappedPorts returns the mapped ports of the runner.
 	MappedPorts() []*dto.MappedPort
 
-	execution.Storage
+	execution.Storer
 	InactivityTimer
 
 	// ExecuteInteractively runs the given execution request and forwards from and to the given reader and writers.
@@ -60,7 +60,7 @@ type Runner interface {
 
 // NomadJob is an abstraction to communicate with Nomad environments.
 type NomadJob struct {
-	execution.Storage
+	execution.Storer
 	InactivityTimer
 	id           string
 	portMappings []nomadApi.PortMapping
@@ -76,7 +76,7 @@ func NewNomadJob(id string, portMappings []nomadApi.PortMapping,
 		id:           id,
 		portMappings: portMappings,
 		api:          apiClient,
-		Storage:      execution.NewLocalStorage(),
+		Storer:       execution.NewLocalStorage(),
 		manager:      manager,
 	}
 	job.InactivityTimer = NewInactivityTimer(job, manager)

internal/runner/runner_test.go

@@ -119,7 +119,7 @@ func (s *ExecuteInteractivelyTestSuite) SetupTest() {
 	s.manager.On("Return", mock.Anything).Return(nil)
 
 	s.runner = &NomadJob{
-		Storage:         execution.NewLocalStorage(),
+		Storer:          execution.NewLocalStorage(),
 		InactivityTimer: s.timer,
 		id:              tests.DefaultRunnerID,
 		api:             s.apiMock,
@@ -225,7 +225,7 @@ func (s *UpdateFileSystemTestSuite) SetupTest() {
 	s.timer.On("ResetTimeout").Return()
 	s.timer.On("TimeoutPassed").Return(false)
 	s.runner = &NomadJob{
-		Storage:         execution.NewLocalStorage(),
+		Storer:          execution.NewLocalStorage(),
 		InactivityTimer: s.timer,
 		id:              tests.DefaultRunnerID,
 		api:             s.apiMock,