KNOX-3071: New ability in list-alias to list for multiple clusters. N…

[hanicz]

…ew create-list-alias command to create multiple aliases for multiple clusters and also list them.

What changes were proposed in this pull request?

This PR proposes a few changes to the KnoxCLI list-alias command and a completely new create-list-aliases command. usage was missing for BatchAliasCreateCommand in printKnoxShellUsage so I added that as well.

With this change the list-alias command will be able to list for multiple clusters. The cluster names have to be concatenated by ':'. It is backward compatible with the current usage so it is able to list for a single cluster as well. Usage: list-alias --cluster1:cluster2:clusterN

The new create-list-alias command can create multiple aliases for multiple clusters with a simple call and list them when they are created. An alias will be created for a cluster if it is listed before the cluster.

Usage: create-list-aliases --alias alias1 --value value1 --alias alias2 --value value2 --cluster cluster1 --alias alias3 --value value3 --cluster cluster2 --alias aliasN --value valueN --cluster clusterN

In the above example alias1 and alias 2 will be created for cluster1, alias3 for cluster2 and aliasN for clusterN. The --value arg is not required as it could be generated or the user will be prompt to provide it.

How was this patch tested?

I wrote new unit tests to cover the new functionalities and tested manually on my local computer.