feat: improved docker image volumes and permissions (#5160)

docker/common/defaults/settings.json

@@ -0,0 +1,8 @@
+{
+  "port": 80,
+  "baseURL": "",
+  "address": "",
+  "log": "stdout",
+  "database": "/database/filebrowser.db",
+  "root": "/srv"
+}