Add API route to list org secrets (#26485)

- Add a new function `CountOrgSecrets` in the file
`models/secret/secret.go`
- Add a new file `modules/structs/secret.go`
- Add a new function `ListActionsSecrets` in the file
`routers/api/v1/api.go`
- Add a new file `routers/api/v1/org/action.go`
- Add a new function `listActionsSecrets` in the file
`routers/api/v1/org/action.go`

go-sdk: https://gitea.com/gitea/go-sdk/pulls/629

---------

Signed-off-by: Bo-Yi Wu <appleboy.tw@gmail.com>
Co-authored-by: Lunny Xiao <xiaolunwen@gmail.com>
Co-authored-by: techknowlogick <matti@mdranta.net>
Co-authored-by: Giteabot <teabot@gitea.io>

modules/structs/secret.go

@@ -0,0 +1,15 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package structs
+
+import "time"
+
+// User represents a secret
+// swagger:model
+type Secret struct {
+	// the secret's name
+	Name string `json:"name"`
+	// swagger:strfmt date-time
+	Created time.Time `json:"created_at"`
+}