[Monitor] Use new slapos.grid.promise from slapos.core to manage promises

Monitor now import slapos.grid.promise from slapos.core to manage promises. promise can be python class which inherit from GenericPromise see: https://lab.nexedi.com/nexedi/slapos.core/blob/master/slapos/grid/promise/

New promises will be placed in slapos.toolbox/slapos/promise/plugin folder.

Only slapgrid will run promises now and will save each result in a json file, monitor only collect results then generate rss and other files. When a partition is correctly deployed, slapgrid will run promise anomaly check, then monitor will read the result to build rss.

monitor-report is removed and not supported anymore.

logrotate and monitor scripts generated in monitor.py is removed, they will be added in buildout