feat: initial app template catalog with 16 apps

Populate the appstore-apptemplates repo with catalog.json and
per-app config files for all 16 curated Docker apps, each at v1.0.0.

apps/wordpress/versions/1.0.0/config.json

@@ -0,0 +1,22 @@
+{
+  "image": "wordpress:latest",
+  "port": 80,
+  "envVars": [
+    {
+      "name": "WORDPRESS_DB_HOST",
+      "required": true
+    },
+    {
+      "name": "WORDPRESS_DB_USER",
+      "default": "wordpress"
+    },
+    {
+      "name": "WORDPRESS_DB_PASSWORD",
+      "required": true
+    },
+    {
+      "name": "WORDPRESS_DB_NAME",
+      "default": "wordpress"
+    }
+  ]
+}