Make temporary image cache configurable

[oliv3r]

trafficstars

Describe the feature you'd like to request

The instructions speak of using /tmp for temporary files and in docker environment its advised to volume mount /tmp.

Would it be possible in addition to using /tmp, maybe use a (configurable) dedicated directory? /tmp/recognize? /var/cache/recognize? This way, we could volume mount the specific path that is needed instead of a broad directory that has much more users.