fix: allow override of artifact server bind address (#1560)

* Prior to this change, the artifact server always binds to the detected
  "outbound IP", breaks functionality when that IP is unroutable.
  For example, Zscaler assigns the host a local CGNAT address,
  100.64.0.1, which is unreachable from Docker Desktop.
* Add the `--artifact-server-addr` flag to allow override of the address
  to which the artifact server binds, defaulting to the existing
  behaviour.

Fixes: #1559

cmd/input.go

@@ -40,6 +40,7 @@ type Input struct {
 	containerCapDrop                   []string
 	autoRemove                         bool
 	artifactServerPath                 string
+	artifactServerAddr                 string
 	artifactServerPort                 string
 	jsonLogger                         bool
 	noSkipCheckout                     bool