refactor: dependency injection instead of package globals (#57)

* refactor: export Settings type, Setup returns value

* refactor: resolver.Setup takes explicit Settings struct

* refactor: GetHeadersWithoutTrustedHeaders takes explicit header params

* refactor: server constructors take narrow config

* refactor: Router struct with handler methods, remove geoSvc global

* refactor: wire DI through main, remove setting.App references

* refactor: remove App global, use returned Settings

* refactor: update router tests for DI

* chore: fix lint issues — rename ServerTimeouts to Timeouts, fix shadowed variables

router/port_scanner.go

@@ -17,7 +17,7 @@ type JSONScanResponse struct {
 	Reason    string `json:"reason"`
 }
 
-func scanTCPPort(ctx *gin.Context) {
+func (rt *Router) scanTCPPort(ctx *gin.Context) {
 	port, err := strconv.Atoi(ctx.Params.ByName("port"))
 	if err == nil && (port < 1 || port > 65535) {
 		err = fmt.Errorf("%d is not a valid port number", port)