Update README for various templates

[gauravAggrhari]

README needs to be updated for the following templates:

• AWS EBS
• AWS EFS
• Azure Block
• NetApp SAN
• NetApp NAS

Please add to the list if any more templates need to be updated.

[mssachan]

NetApp SAN:
Need to update SC related names/keywords in this section: https://github.com/IBM/ibm-satellite-storage/tree/develop/config-templates/netapp/netapp-ontap-san/21.04#verifying-your-netapp-ontap-san-driver-storage-configuration-is-assigned-to-your-clusters
Similarly for NetApp NAS: https://github.com/IBM/ibm-satellite-storage/tree/develop/config-templates/netapp/netapp-ontap-nas/21.04#verifying-your-netapp-ontap-nas-driver-storage-configuration-is-assigned-to-your-clusters

Update for both versions 20.07 & 21.04