enhance nova list output with new three fields

Nova list to accept a new parameter --maximal. Using --maximal option we can have three new fields.
These three new files are

Flavor-name
availability-zone-list
image-name

This three fields will enhance the output of nova list, to further analysis.

Currently we have added Availability Zone to "nova list --maximal". You can see following output.

+--------------------------------------+-----------------------+-------------------+--------+------------+-------------+-------------------+
| ID | Name | Availability Zone | Status | Task State | Power State | Networks |
+--------------------------------------+-----------------------+-------------------+--------+------------+-------------+-------------------+
| a9e1001c-f29d-467b-8b43-1267751a8368 | MME-GP-2.3_testserver | nova | ACTIVE | - | Running | private=10.0.0.27 |
| f0b290af-a555-470c-9f13-6bf72b9a0f35 | anusha | nova | ACTIVE | - | Running | private=10.0.0.24 |
| 1ac37486-f5c1-42e1-b632-e33b32fbe785 | test | nova | ACTIVE | - | Running | public=172.24.4.4 |
| 1fdab6ab-7a9a-4fa1-a6e1-52a648dbbf00 | test2 | nova | ACTIVE | - | Running | public=172.24.4.5 |
+--------------------------------------+-----------------------+-------------------+--------+------------+-------------+-------------------+

In the similar way, flavor-name and image-name will be added.