option to append timestamp prefix to workflow name when workflowtemplate is submitted via cli

[tooptoop4]

currently if u have deployed a workflowtemplate and then try to submit a run of it via the cli it will generate a workflow name with 5 random chars on the end of it. would like that it generates a workflow name with the timestamp in the name too. 2 benefits: easy to see from the name when it was submitted, less chance of a name collision from 10000s of runs

[tczhao]

make generateName configurable does sound like an awesome idea