feat: Konnector worker honors skip-maintenance-for

  The `harvest.skip-maintenance-for` flag can be set to a list of
  konnector slugs to unlock these in Harvest and allow requesting an
  execution even if it's maintenance mode has been activated either in
  the registry or cozy-stack.

  However, the flag was not honored in the konnector worker thus
  preventing its execution.
  We'll now check if the konnector to be executed is part of the list
  (if set) and skip the maintenance mode when appropriate.

worker/exec/konnector.go

@@ -15,6 +15,7 @@ import (
 
 	"github.com/cozy/cozy-stack/model/account"
 	"github.com/cozy/cozy-stack/model/app"
+	"github.com/cozy/cozy-stack/model/feature"
 	"github.com/cozy/cozy-stack/model/instance"
 	"github.com/cozy/cozy-stack/model/instance/lifecycle"
 	"github.com/cozy/cozy-stack/model/job"
@@ -126,6 +127,21 @@ func beforeHookKonnector(j *job.Job) (bool, error) {
 
 	if err := json.Unmarshal(j.Message, &msg); err == nil {
 		slug = msg.Konnector
+
+		inst, err := lifecycle.GetInstance(j.DomainName())
+		if err != nil {
+			return false, err
+		}
+
+		flags, err := feature.GetFlags(inst)
+		if err != nil {
+			return false, err
+		}
+		skipMaintenance, err := flags.HasListItem("harvest.skip-maintenance-for", slug)
+		if err != nil {
+			return false, err
+		}
+
 		doc, err := app.GetMaintenanceOptions(slug)
 		if err != nil {
 			j.Logger().Warnf("konnector %q could not get local maintenance status", slug)
@@ -136,22 +152,31 @@ func beforeHookKonnector(j *job.Job) (bool, error) {
 					return true, nil
 				}
 			}
-			j.Logger().Infof("konnector %q has not been triggered because of its maintenance status", slug)
-			return false, nil
-		}
-		inst, err := lifecycle.GetInstance(j.DomainName())
-		if err != nil {
-			return false, err
+
+			if skipMaintenance {
+				j.Logger().Infof("skipping konnector %q's maintenance", slug)
+				return true, nil
+			} else {
+				j.Logger().Infof("konnector %q has not been triggered because of its maintenance status", slug)
+				return false, nil
+			}
 		}
+
 		app, err := registry.GetApplication(slug, inst.Registries())
 		if err != nil {
 			j.Logger().Warnf("konnector %q could not get application to fetch maintenance status", slug)
 		} else if app.MaintenanceActivated {
 			if j.Manual && !app.MaintenanceOptions.FlagDisallowManualExec {
 				return true, nil
 			}
-			j.Logger().Infof("konnector %q has not been triggered because of its maintenance status", slug)
-			return false, nil
+
+			if skipMaintenance {
+				j.Logger().Infof("skipping konnector %q's maintenance", slug)
+				return true, nil
+			} else {
+				j.Logger().Infof("konnector %q has not been triggered because of its maintenance status", slug)
+				return false, nil
+			}
 		}
 
 		if msg.BIWebhook {