[Monitoring] Update Beats Template with Metrics (elastic/x-pack-elasticsearch#2902)
[Monitoring] Update Beats Template with Metrics (elastic/x-pack-elasticsearch#2902)

* [Monitoring] Update Beats Template with Metrics

- remove source_node.timestamp
- includes mapping for beat type = Metricbeat

* remove metricbeat and xpack objects which are not used in the UI

* use long instead of integer type

Original commit: elastic/x-pack-elasticsearch@083b9cc5755053ab0e5b6adc1b3554eec9da1109

GlenRSmith/elasticsearch,HonzaKral/elasticsearch,HonzaKral/elasticsearch,uschindler/elasticsearch,nknize/elasticsearch,robin13/elasticsearch,GlenRSmith/elasticsearch,GlenRSmith/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,gfyoung/elasticsearch,gingerwizard/elasticsearch,gfyoung/elasticsearch,nknize/elasticsearch,scorpionvicky/elasticsearch,uschindler/elasticsearch,scorpionvicky/elasticsearch,robin13/elasticsearch,nknize/elasticsearch,coding0011/elasticsearch,gingerwizard/elasticsearch,uschindler/elasticsearch,robin13/elasticsearch,coding0011/elasticsearch,robin13/elasticsearch,gingerwizard/elasticsearch,gingerwizard/elasticsearch,nknize/elasticsearch,nknize/elasticsearch,coding0011/elasticsearch,robin13/elasticsearch,coding0011/elasticsearch,gfyoung/elasticsearch,coding0011/elasticsearch,uschindler/elasticsearch,HonzaKral/elasticsearch,gingerwizard/elasticsearch,GlenRSmith/elasticsearch,gfyoung/elasticsearch,scorpionvicky/elasticsearch,gfyoung/elasticsearch,gingerwizard/elasticsearch,scorpionvicky/elasticsearch,scorpionvicky/elasticsearch,GlenRSmith/elasticsearch