[UI][EDP] Support job relaunch

Once I've configured and run a job, I would like to be able to easily rerun it with different data. In general, this is easy to do for jobs that do not require much configuration (or params/args), but for a job that has a lot of configuration, it would require several clicks and a lot of typing to get the configuration entered for another run.

I have a couple of proposals on how to accomplish this.

1) Add a text area to the Job Configuration page where the config values can be readily copy/pasted.

or

2) From the Job Executions page, add a "relaunch" button that would bring up the launch dialog prepopulated with the data from the previous run.

Ideally, both of these would be implemented to bolster the user experience, but even one of them would allow my use case to flow better than it currently does.

The notes can be found at https://etherpad.openstack.org/p/savanna-icehouse-roadmap (Under the "must have" section).

Based on https://bugs.launchpad.net/savanna/+bug/1241136