add configurable punching delay because of race-condition-y conntracks (#210)

* add configurable punching delay because of race-condition-y conntracks

* add changelog

* fix tests

* only do one punch per query

* Coalesce punchy config

* It is not is not set

* Add tests

Co-authored-by: Nate Brown <nbrown.us@gmail.com>

punchy.go

@@ -0,0 +1,30 @@
+package nebula
+
+import "time"
+
+type Punchy struct {
+	Punch   bool
+	Respond bool
+	Delay   time.Duration
+}
+
+func NewPunchyFromConfig(c *Config) *Punchy {
+	p := &Punchy{}
+
+	if c.IsSet("punchy.punch") {
+		p.Punch = c.GetBool("punchy.punch", false)
+	} else {
+		// Deprecated fallback
+		p.Punch = c.GetBool("punchy", false)
+	}
+
+	if c.IsSet("punchy.respond") {
+		p.Respond = c.GetBool("punchy.respond", false)
+	} else {
+		// Deprecated fallback
+		p.Respond = c.GetBool("punch_back", false)
+	}
+
+	p.Delay = c.GetDuration("punchy.delay", time.Second)
+	return p
+}