Since metrics on dropped packets are counters, the alerts should use
the rate() function. This change also fixes some inconsistencies in the
alert descriptions.

Change-Id: I9abbc0a49f45ba760836c436a3e7e65aa62f652e

Change-Id: I1cc00b41a6a1774d1401a9f71ab4c6364c65d139

Change-Id: Idc73c152a0e71d5ac2a8c10f46c955755d8e77ae

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: If50f18367b22338b3fba1ff15902d557a0bdf2ea

Change-Id: I54e02e0741d53ec7b2335145dc968b7b8c8f5e00

Change-Id: I1765fc6aa4a8c3da25330f19bb043ddbf548b9ad

Change-Id: I66576b4ed40ef160c5f13747a908f018f252b6b4