Update horizon config options

Set horizon option below in the following order:
- IMAGES_ALLOW_LOCATION

1. From pillar data:
horizon:server:images_allow_location

2 From glance mine function:
set the IMAGES_ALLOW_LOCATION according
to the glance:server:show_multiple_locations pillar data

3. Default
IMAGES_ALLOW_LOCATION = True

Change-Id: If613cff0286f8cf784112fdcdb0946729924003e
Related-Prod: PROD-21005
3 files changed