Add -create-plan flag to 'src action exec'

Created by: mrnugget

When the -create-plan flag is given the src action exec command will create a campaign plan from the produced patches, making it not necessary to pipe the output to src campaign plan create-from-patches.

If the execution of the action failed in a subset of the repositories, the user is prompted and asked whether they would create a campaign plan from the successfully produced patches or not.