Fix review comments and new changes in config (#8515)

- Migrate and save only settings which are enabled
- Rename logger_http to logger_webhook and
  logger_http_audit to audit_webhook
- No more pretty printing comments, comment
  is a key=value pair now.
- Avoid quotes on values which do not have space in them
- `state="on"` is implicit for all SetConfigKV unless
  specified explicitly as `state="off"`
- Disabled IAM users should be disabled always

cmd/admin-handlers-config-kv.go

@@ -24,6 +24,7 @@ import (
 	"io"
 	"net/http"
 	"strconv"
+	"strings"
 
 	"github.com/gorilla/mux"
 	"github.com/minio/minio/cmd/config"
@@ -147,15 +148,14 @@ func (a adminAPIHandlers) SetConfigKVHandler(w http.ResponseWriter, r *http.Requ
 		}
 	}
 
-	defaultKVS := configDefaultKVS()
 	oldCfg := cfg.Clone()
 	scanner := bufio.NewScanner(bytes.NewReader(kvBytes))
 	for scanner.Scan() {
-		// Skip any empty lines
-		if scanner.Text() == "" {
+		// Skip any empty lines, or comment like characters
+		if scanner.Text() == "" || strings.HasPrefix(scanner.Text(), config.KvComment) {
 			continue
 		}
-		if err = cfg.SetKVS(scanner.Text(), defaultKVS); err != nil {
+		if err = cfg.SetKVS(scanner.Text()); err != nil {
 			writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
 			return
 		}
@@ -307,7 +307,6 @@ func (a adminAPIHandlers) RestoreConfigHistoryKVHandler(w http.ResponseWriter, r
 		}
 	}
 
-	defaultKVS := configDefaultKVS()
 	oldCfg := cfg.Clone()
 	scanner := bufio.NewScanner(bytes.NewReader(kvBytes))
 	for scanner.Scan() {
@@ -315,7 +314,7 @@ func (a adminAPIHandlers) RestoreConfigHistoryKVHandler(w http.ResponseWriter, r
 		if scanner.Text() == "" {
 			continue
 		}
-		if err = cfg.SetKVS(scanner.Text(), defaultKVS); err != nil {
+		if err = cfg.SetKVS(scanner.Text()); err != nil {
 			writeErrorResponseJSON(ctx, w, toAdminAPIErr(ctx, err), r.URL)
 			return
 		}