Added mixin for common text rendering code

components/lenses/renderers/mixins/TextContentRendererMixin.js

@@ -0,0 +1,10 @@
+export default {
+  props: {
+    response: {},
+  },
+  computed: {
+    responseBodyText() {
+      return new TextDecoder("utf-8").decode(this.response.body)
+    },
+  },
+}