Allow the regionName attribute to be set as a SystemGroup, so it become a generic scope way of filtering regions

[Joe-Winchester]

The CICS Profile attribute regionName is used in the CMCI requests as the scope, which means it can take a valid CICSSystemGroup value. This works for CICS CLI profiles although the documentation doesn't describe this behavior and issue zowe/cics-for-zowe-client#75 is to update the documentation.

Currently when a SystemGroup is entered in a regionName field the tree treats the SystemGroup as a region, tries to check the managed region table to check whether it's active, and shows it as an unmanaged region. The fix would be to check the CICSSystemGroup table, realize it's a group, use a group graphic, and show the resource nodes for Program/LocalFile/Transaction as occurs currently.

Also update the create profile UI to let users know that they can specify regionName or systemGroup in the --regionName field.

This feature will allow users to filter regions in a plex by specifying the system group, which allows developers to focus in on the resources in the plex for the regions that make up the application the are working on, rather than having to do client side filtering of the region (which has poorer performance when showing all resources for a resource type across a client side filtered plex).