FR: pretty prints for LTM commands

[lrumancik]

LTM commands such as ltm-info and commands to launch tests directly return the json response from the LTM server. When many tests and/or configs are running, the ltm-info ouptut can get very long. It would be nice to have a summarized version of the test statuses. We might as well cleanup the other commands which also print the json.

Note some functions rely on parsing the json directly to get specific fields. If we make pretty print the default, we would want to add a --json flag which can return the json for these cases.