feat(refacto): move everything in internal package

This allows to install katenary with `go install` and to clean up the
project folder.

internal/generator/labels/labelstructs/secrets_test.go

@@ -0,0 +1,17 @@
+package labelstructs
+
+import "testing"
+
+func TestSecretLabel(t *testing.T) {
+	data := "- foo\n- bar"
+	tc, err := SecretsFrom(data)
+	if err != nil {
+		t.Errorf("Error parsing SecretLabel: %v %v", err, tc)
+	}
+	items := []string{"foo", "bar"}
+	for i, item := range tc {
+		if item != items[i] {
+			t.Errorf("Expected SecretLabel to contain '%s', got '%s'", items[i], item)
+		}
+	}
+}