feat: rename main.go to badger.go to allign with traefik best practices and add test coverage

Signed-off-by: Marc Schäfer <git@marcschaeferger.de>

ips/ips_test.go

@@ -0,0 +1,18 @@
+package ips
+
+import (
+	"net"
+	"testing"
+)
+
+func TestCFIPs(t *testing.T) {
+	cidrs := CFIPs()
+	if len(cidrs) == 0 {
+		t.Fatal("CFIPs() returned an empty list")
+	}
+	for _, cidr := range cidrs {
+		if _, _, err := net.ParseCIDR(cidr); err != nil {
+			t.Errorf("CFIPs() returned invalid CIDR %q: %v", cidr, err)
+		}
+	}
+}