Email and reporting

This is part 1 of the autotest reporting work, as described on:

https://github.com/autotest/autotest/issues/662

The summary of this work is:

 * Dump client job data to a JSON file
 * Render the local HTML report using a newly added templating engine called jsontemplate
 * Reorganize global_config.ini, including new EMAIL and NOTIFICATION sections
 * Unify email sending, that had disparate implementations inside autotest into a single API
 * Make aborted/failed jobs to report to the grid admin instead of the job submitter

Next steps are

 * Re-queue a job that failed
 * Add emergency notifications to the grid admin when jobs started to fail