Updates to the 'Launch and manage instances' section

Included the following updates:
* Option 'Delete on Terminate' to delete a volume when an instance is
terminated.
* Note regarding the Flavor field being selected based on the minimum image
requirements.
* New 'Advanced Options' tab option in the 'Launch Instance' window for
selecting the type of disk partition.
* Minor updates to 'Create Snapshots' section.
Partial-Bug: #1307860

Change-Id: Ic23fcb4612e0d16505d509c80c20b18a89e0bb1c
Merge "Updates to the 'Launch and manage instances' section"