Move `location`'s domain code out of glance.store

This patch moves the location domain's specific code out of
glance.store. Since this code is Glance specific, it's necessary to move
it out of the store package so that we can then remove it all together
and use the `glance.store` library.

Partially-Implements blueprint: create-store-package

Change-Id: I7dc3d5d211054cabc2adc2b9b689cda11bce2190
Merge "Move `location`'s domain code out of glance.store"