Fix access log (#14475)

Fix #14121, #14478.

The `AccessLog` middleware has to be after `Contexter` or `APIContexter` so that we can get `LoginUserName` if possible.
And also there is a **BREAK** change that it removed internal API access log.

modules/context/response.go

@@ -12,6 +12,7 @@ type ResponseWriter interface {
 	Flush()
 	Status() int
 	Before(func(ResponseWriter))
+	Size() int
 }
 
 var (
@@ -21,11 +22,17 @@ var (
 // Response represents a response
 type Response struct {
 	http.ResponseWriter
+	written        int
 	status         int
 	befores        []func(ResponseWriter)
 	beforeExecuted bool
 }
 
+// Size return written size
+func (r *Response) Size() int {
+	return r.written
+}
+
 // Write writes bytes to HTTP endpoint
 func (r *Response) Write(bs []byte) (int, error) {
 	if !r.beforeExecuted {
@@ -35,8 +42,9 @@ func (r *Response) Write(bs []byte) (int, error) {
 		r.beforeExecuted = true
 	}
 	size, err := r.ResponseWriter.Write(bs)
+	r.written += size
 	if err != nil {
-		return 0, err
+		return size, err
 	}
 	if r.status == 0 {
 		r.WriteHeader(200)