Move cloud metadata packages and kubernetes resources marshaling to internal

Decouples cloud provider metadata packages from kubernetes related code

Signed-off-by: Malte Poll <mp@edgeless.systems>

internal/cloud/gcp/autoscaler_test.go

@@ -0,0 +1,19 @@
+package gcp
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func TestTrivialAutoscalerFunctions(t *testing.T) {
+	assert := assert.New(t)
+	autoscaler := Autoscaler{}
+
+	assert.NotEmpty(autoscaler.Name())
+	assert.Empty(autoscaler.Secrets("", ""))
+	assert.NotEmpty(autoscaler.Volumes())
+	assert.NotEmpty(autoscaler.VolumeMounts())
+	assert.NotEmpty(autoscaler.Env())
+	assert.True(autoscaler.Supported())
+}