Added volume module for Google Cloud NetApp Volume (GoogleCloudPlatfo…

…rm#9513)

* added volume module

* Added updated function and network fix

* updated update test fields.

* updated unixPermissions field.

* updated test file for snapshot_policy

* updated description.
updated test file with basic example and function name.

* removed the *_UNSPECIFIED values for inputs
Default values for minutes, hours, days and day_of_week in snapshot block
Updated tests to incorporate suggestions by shuya
Fixes some indentation in tests
Updates some test to get better test coverage
commented restoreParamters as suggested by Shuya.

* updated tests to use us-west1 region

* updated region to us-west2