Move pool path validation logic to housekeeping package

Object pool paths are validated to match a regex of the pool paths Rails is generating. As Praefect will soon be generating the disk paths, the path of the pools will no longer match what Rails is generating with the @pools/xx/xx/xxxx format. Pool paths are also verified in the housekeeping package to avoid pruning objectp pools. This commit moves the pool path checking logic to the houskeeping package so it can be shared between the objectpool and housekeeping packages. It's not possible to locate the shared functionality in git nor the objectpool packages due to cyclic dependencies between them. With the check in a common place, a follow up commit can later add validation regexp for Praefect generated pool paths.

Part of #3485 (closed)