Since we added to nstat's telegraf plugin the possibility
to collect data from `/proc/net/softnet_stat` regarding
dropped packets and rx_net_action a.k.a time squeeze, we need to enable
it globally on all hosts.

Also grafana dashboard update to include new graphs + added four
new Prometheus alers.

Related-Bug: PROD-21090

Change-Id: I9dfe87bdc8b677a51e3f305dd3c75c7d4cc4e0d4

Change-Id: I6b21bed3dd2c632af8274769b562f366c4057b82
Closes-Prod: PROD-20090

Change-Id: Icf8d0fde5120012b449befc8cd4ebea915da9d0d
Partial-Bug: PROD-16264

Change-Id: Ic92564d97000c8bbb824a678af0c9cb7521eaa7e

This change adds the Telegraf configuration to collect swap metrics, the
associated Prometheus alarms and graphs to the Grafana dashboard.

Change-Id: I3595fd0b8cab06215c620642da69dd29c398396a

Change-Id: Icacb0ca22a34f1ff438a895700040563d250bac9