Backported changes to image_info from master branch

Added ci integration tests, updated return value documentation and
refactored to simplify code. Reverted changes such as function calls
and return values which would break backward compatibility with
previous collection releases.

Change-Id: Ibf934568f069c305747fc24fbb22ce3fc095286c
(cherry picked from commit c1a9794207)

ci/roles/image_info/defaults/main.yml

@@ -0,0 +1,23 @@
+expected_fields:
+  - checksum
+  - container_format
+  - created_at
+  - direct_url
+  - disk_format
+  - file
+  - id
+  - locations
+  - metadata
+  - min_disk
+  - min_ram
+  - name
+  - os_hidden
+  - owner
+  - properties
+  - schema
+  - size
+  - status
+  - tags
+  - updated_at
+  - virtual_size
+  - visibility