add DNAs page to nav and other references

src/pages/_data/navigation/mainNav.json5

@@ -30,6 +30,7 @@
             { title: "Lifecycle Events and Callbacks", url: "/build/callbacks-and-lifecycle-hooks/" },
             { title: "Zome Functions", url: "/build/zome-functions/" },
           ] },
+          { title: "DNAs", url: "/build/dnas/" }
         ]},
         { title: "Working with Data", url: "/build/working-with-data/", children: [
           { title: "Identifiers", url: "/build/identifiers/" },

src/pages/build/application-structure.md

@@ -9,7 +9,7 @@ title: Application Structure
     * [Zomes](/build/zomes/) --- integrity vs coordinator, how to structure and compile
         * [Lifecycle Events and Callbacks](/build/callbacks-and-lifecycle-hooks/) --- writing functions that respond to events in a hApp's lifecycle
         * [Zome Functions](/build/zome-functions/) --- writing your hApp's back-end API
-    * DNAs (coming soon) --- what they're used for, how to specify and bundle
+    * [DNAs](/build/dnas/) --- what they're used for, how to specify and bundle
     * hApps (coming soon) --- headless vs UI-based, how to bundle and distribute
 :::
 
@@ -63,6 +63,8 @@ This means you can hot-swap coordinators as you fix bugs and add features, witho
 
 Because each DNA has its own separate peer network and data store, you can use the DNA concept to come up with creative approaches to [privacy](https://dialnet.unirioja.es/servlet/articulo?codigo=8036267) and access, separation of responsibilities, or data retention.
 
+[Read more on the DNAs page](/build/dnas/).
+
 ### hApp
 
 One or more DNAs come together in a **hApp** (Holochain app). Each DNA fills a named **role** in the hApp, and you can think of it like a [microservice](https://en.wikipedia.org/wiki/Microservices).