#119 add support for storage class

[planetf1]

• Adds support for specification of storage class
• Adds simple example

To use

helm install <blah blah> --set storageClassName='ibmc-vpc-block-general-purpose'

or

helm install <blah blah> -f config/values/lab-storageclass.yaml

The same storageclass will be used for all allocations. No other customizations are possible.

This has been implemented in base & lab charts