Add ANSIBLE_JSON_INDENT parameter to both the json and jsonl callback
plugins. The default values are different between the two modules to
maintain their existing behavior:
* json: indent==4, causing a prettyprint output
* jsonl: indent==0, causing a 1-line output
One specific use-case that is enabled by this feature: if a user
chooses to use the jsonl plugin so that they still get output at the
end of each task (vs. only at the end of the play), they may also want
human-readable output so that they can monitor the status of their
play. For example, setting the jsonl indent level to 4 gives a)
output at the end of each task, and b) making that output be both
machine readable and human readable.
Signed-off-by: Jeff Squyres <jsquyres@cisco.com>
