chore: Remove dogstatsd variable and references

This came up as we have this field in the documentation but clairctl
will error out if it's used when invoking any command.

Signed-off-by: crozzy <[email protected]>

Author: crozzy

Documentation/reference/config.md

@@ -103,8 +103,6 @@ metrics:
     name: ""
     prometheus:
         endpoint: null
-    dogstatsd:
-        url: ""
 ```
 
 Note: the above just lists every key for completeness. Copy-pasting the above as

introspection/server.go

@@ -24,7 +24,6 @@ import (
 const (
 	Prom                     = "prometheus"
 	DefaultPromEndpoint      = "/metrics"
-	DogStatsD                = "dogstatsd"
 	Stdout                   = "stdout"
 	Jaeger                   = "jaeger"
 	HealthEndpoint           = "/healthz"