Add Prowlarr Cloudron package

- Add CloudronManifest.json with proper metadata
- Add Dockerfile to build Prowlarr container
- Add start.sh script to launch Prowlarr
- Add icon.png for the app
- Remove old LICENSE and README.md files

CloudronManifest.json

@@ -0,0 +1,19 @@
+{
+    "id": "com.prowlarr.cloudronapp",
+    "title": "Prowlarr",
+    "author": "Prowlarr Team",
+    "description": "Prowlarr is an indexer manager/proxy built on the popular *arr .net/reactjs base stack, integrating with your various PVR apps.",
+    "tagline": "Indexer Manager for Usenet and BitTorrent",
+    "version": "1.0.0",
+    "healthCheckPath": "/",
+    "httpPort": 9696,
+    "addons": {
+      "localstorage": {}
+    },
+    "manifestVersion": 2,
+    "website": "https://prowlarr.com",
+    "contactEmail": "support@prowlarr.com",
+    "icon": "file://icon.png",
+    "tags": [ "indexer", "torrent", "usenet", "pvr" ],
+    "mediaLinks": [ "https://raw.githubusercontent.com/Prowlarr/Prowlarr/develop/Logo/256.png" ]
+  }