feat: added keyword codec (partially works)

registry/templates/Review.marka

@@ -0,0 +1,42 @@
+---
+{
+  path: .
+  codec: yaml
+  fields:
+    - path: "@context"
+      codec: const
+      value: https://schema.org
+      hidden: true
+    - path: "@schema"
+      codec: const
+      value: Review
+      hidden: true
+    - path: "@type"
+      codec: const
+      value: Review
+    - path: tmdbId
+    - path: image
+    - path: author.name
+    - path: author.@type
+      codec: const
+      value: Person
+      hidden: true
+    - path: datePublished
+    - path: itemReviewed.name
+    - path: reviewRating.ratingValue
+    - path: reviewRating.bestRating
+      codec: const
+      value: 5
+      hidden: true
+    - path: reviewRating.worstRating
+      codec: const
+      value: 1
+      hidden: true
+    - path: reviewBody
+}
+---
+
+# { itemReviewed.name }
+{ keywords | hashtags }
+
+{ reviewBody }