[patch] Fix must-gather useability issues

[durera]

When running mas must-gather and no Suite instance is found there will be an error message printed:

IBM Maximo Application Suite Must-Gather Tool
 
Must gather will be saved to: /workspace/mustgather/pwmasdev-install-hkzkw/must-gather-20230503-151813.tgz
Generate Dependency Report
- Cluster Namespaces
- IBM CloudPak Foundation Services
- IBM CloudPak for Data
- IBM Db2 universal Operator
error: the server doesn't have a resource type "suite"

This is misleading and gives the impression must-gather failed; it's just we are not capturing the err from looking up whether there are any MAS instances to collect gather from. In the case there is no MAS instance, we still want to collect the must-gather and we don't want to give the impression there was an error generating it.

An additional confirmation the must-gather was generated is also now provided:

mas must-gather --help is also now implemented: