Incorporate changes from @wyattwalter

https://github.com/wyattwalter/grafana-tools/commit/89c177a124a881136bdd99600b0004fb5c8eefd3

Original commit comment:
cleanup of backup script

 - os.rename doesn't work across devices, change to shtutil.move
 - add index name as argument
 - cleanup names of files inside tarball
 - query for more dashboards from ES
Pass debug option as argument