Temporarily disable appdash from docker-compose

Until I read the doc and find how to limit the retention,
otherwise it just eats all my ram and cpu and things start to fall
apart.

PUBLISHED_FROM=eb33fb44736f07b992270689217aca4af70513ff

docs/usage-example/items.json

@@ -1,5 +0,0 @@
-{
-  "items": [
-    { "type": "markdown", "name": "intro.md" }
-  ]
-}