cloud/shepherd: add equinix API metrics

This adds the following signals to our interaction with the Equinix API:

 1. Latency
 2. Traffic
 3. Errors
 4. Saturation

Change-Id: Ic2d5e36a7a26ab906ac1c2fa6741ebf86b9e551a
Reviewed-on: https://review.monogon.dev/c/monogon/+/1606
Tested-by: Jenkins CI
Reviewed-by: Tim Windelschmidt <tim@monogon.tech>
diff --git a/cloud/shepherd/equinix/manager/server/main.go b/cloud/shepherd/equinix/manager/server/main.go
index 21e7e5a..984d96f 100644
--- a/cloud/shepherd/equinix/manager/server/main.go
+++ b/cloud/shepherd/equinix/manager/server/main.go
@@ -68,6 +68,7 @@
 	if c.API.APIKey == "" || c.API.User == "" {
 		klog.Exitf("-equinix_api_username and -equinix_api_key must be set")
 	}
+	c.API.MetricsRegistry = registry
 	api := wrapngo.New(&c.API)
 
 	// These variables are _very_ important to configure correctly, otherwise someone