Restore alerts in prometheus and dashboards in grafana

[eloiferrer]

Issue description:

• Alerts and dashboards were lost when moving to the new server and have to be added again manually.
• Grafana dashboards were backed up as json, but prometheus needs to be configured before they can be restored.
• Alerts also have to be created again, for the following cases:
  • Portal is down
  • Scholia is down
  • Blazegraph synchronizer is down
  • Back up failed

TODOS:

• [ ] Configure prometheus metrics
• [ ] Setup alerts
• [ ] Restore dashboards from .json files
• [ ] Track grafana dashboard and configuration in github (see https://github.com/mpostument/grafana-sync and https://github.com/Beam-Connectivity/grafana-dashboard-manager)
• [ ] Remove current dashboard backup script (after implementation of github synchronization)

Acceptance-Criteria

Checklist for this issue:

• [x] Assignee has been set for this issue
• [x] All fields of the issue have been filled
• [ ] Issue has been assigned to the main project
• [ ] Code was merged
• [ ] Feature branch has been deleted and issues were updated / closed
• [x] Issue is tracked by an epic, or the label 'non-epic' is set to the issue.

[LizzAlice]

• [ ] Get dashboards running:
  • [ ] Backup monitor
  • [ ] node exporter
  • [x] traefik
  • [x] traefik 2
  • [x] watchtower
• [ ] configure email alerts
  • [x] portal down
  • [x] scholia down
  • [ ] blazegraph synchronizer down
  • [ ] back up failed