Updating Aggregators and Adding plugin folder

See merge request !1

Updating bin/smartdata/Aggregators.php to add Aggregators to developed on 2019-2.
Updating lib files to include those aggregators.
Uploading the smartdata_grafana_plugin, with the code that when compiled generates the lib folder.
Lib folder's content is the one we put on the server. This content is generated using the plugin code, that was originally placed at https://epos.lisha.ufsc.br/svn/makers/smartdata_grafana_plugin/.
A tutorial of how to do this process is available at https://epos.lisha.ufsc.br/IoT+Internals#Grafana_Integration. However, it is a bit outdated. Should I update the page at epos site or create a README inside the plugin folder on gitlab?