Make default uvol database path configurable

In OpenWrt-based systems, the blockd service is responsible for dynamically establishing mount points for storage volumes. The existing methodology, which relies on predefined paths, may lead to unnecessary writing operations on the flash storage. Therefore, it's proposed to allow customization of the storage path to enable redirection to a tmpfs-supported location, thereby reducing the wear and tear on the flash memory.

References: !109 (closed)