Add author, image query partials

Author: ravewebdev

api/wordpress/_partials/authorPostFields.js

@@ -0,0 +1,10 @@
+// Query partial: retrieve author post fields.
+const authorPostFields = `
+  author {
+    node {
+      slug
+      nickname
+    }
+  }
+`
+export default authorPostFields

api/wordpress/_partials/featuredImagePostFields.js

@@ -0,0 +1,11 @@
+// Query partial: retrieve featured image post fields.
+const featuredImagePostFields = `
+  featuredImage {
+    node {
+      altText
+      sourceUrl(size: $imageSize)
+    }
+  }
+`
+
+export default featuredImagePostFields