Secure Traefik Dashboard

[aklinker1]

Right now, we're passing --api.insecure=true to allow access to the traefik dashboard on port 8080, but that allows everyone access to the dashboard. Lets add additional configuration to the Traefik Plugin's config, so that we can enable the secure dashboard with basic auth:

type TraefikConfig struct {
	EnableHttps       bool   `mapstructure:"enableHttps"`
	CertEmail         string `mapstructure:"certEmail"`
	CertsDir          string `mapstructure:"dataDir"`
+	SecureDashboard   bool   `mapstructure:"secureDashboard"`
+	DashboardRoute    string `mapstructure:"dashboardRoute"`
+	DashboardUsername string `mapstructure:"dashboardUsername"`
+	DashboardHtPasswd string `mapstructure:"dashboardHtPasswd"`
}