Include iso as supported disk_format

iso is a supported type for disk_format, include it as
a supported property value

Change-Id: I7026a8e4bae235acaae0a9856fab8a47ccb3e49e
Disable 80chars/class_parameter_defaults checks

* Disable warnings for "line has more than 80 characters"
* Disable warnings for "parameterised class parameter without a default value"

We do not wish to track warnings for such violations.

Change-Id: Idb3828f7b19c39ebcb84c4ad8f415aefef84cf21