Add get actions runner registration token for API routes, repo, org, user and global level (#27144)

Replace #23761

---------

Co-authored-by: Denys Konovalov <kontakt@denyskon.de>
Co-authored-by: techknowlogick <techknowlogick@gitea.io>

routers/api/v1/admin/runners.go

@@ -0,0 +1,26 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package admin
+
+import (
+	"code.gitea.io/gitea/modules/context"
+	"code.gitea.io/gitea/routers/api/v1/shared"
+)
+
+// https://docs.github.com/en/rest/actions/self-hosted-runners?apiVersion=2022-11-28#create-a-registration-token-for-an-organization
+
+// GetRegistrationToken returns the token to register global runners
+func GetRegistrationToken(ctx *context.APIContext) {
+	// swagger:operation GET /admin/runners/registration-token admin adminGetRunnerRegistrationToken
+	// ---
+	// summary: Get an global actions runner registration token
+	// produces:
+	// - application/json
+	// parameters:
+	// responses:
+	//   "200":
+	//     "$ref": "#/responses/RegistrationToken"
+
+	shared.GetRegistrationToken(ctx, 0, 0)
+}