Limit how often a busy tunnel can requery the lighthouse (#940)

Co-authored-by: Wade Simmons <wadey@slack-corp.com>

config/config.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"fmt"
 	"io/ioutil"
+	"math"
 	"os"
 	"os/signal"
 	"path/filepath"
@@ -236,6 +237,15 @@ func (c *C) GetInt(k string, d int) int {
 	return v
 }
 
+// GetUint32 will get the uint32 for k or return the default d if not found or invalid
+func (c *C) GetUint32(k string, d uint32) uint32 {
+	r := c.GetInt(k, int(d))
+	if uint64(r) > uint64(math.MaxUint32) {
+		return d
+	}
+	return uint32(r)
+}
+
 // GetBool will get the bool for k or return the default d if not found or invalid
 func (c *C) GetBool(k string, d bool) bool {
 	r := strings.ToLower(c.GetString(k, fmt.Sprintf("%v", d)))