move the gitea admin subcommands into separate files (#27307)

As title.
Probably it's better to put those sub cmd to different dirs. Will do
that in the future.

cmd/admin_regenerate.go

@@ -0,0 +1,46 @@
+// Copyright 2023 The Gitea Authors. All rights reserved.
+// SPDX-License-Identifier: MIT
+
+package cmd
+
+import (
+	asymkey_model "code.gitea.io/gitea/models/asymkey"
+	"code.gitea.io/gitea/modules/graceful"
+	repo_service "code.gitea.io/gitea/services/repository"
+
+	"github.com/urfave/cli/v2"
+)
+
+var (
+	microcmdRegenHooks = &cli.Command{
+		Name:   "hooks",
+		Usage:  "Regenerate git-hooks",
+		Action: runRegenerateHooks,
+	}
+
+	microcmdRegenKeys = &cli.Command{
+		Name:   "keys",
+		Usage:  "Regenerate authorized_keys file",
+		Action: runRegenerateKeys,
+	}
+)
+
+func runRegenerateHooks(_ *cli.Context) error {
+	ctx, cancel := installSignals()
+	defer cancel()
+
+	if err := initDB(ctx); err != nil {
+		return err
+	}
+	return repo_service.SyncRepositoryHooks(graceful.GetManager().ShutdownContext())
+}
+
+func runRegenerateKeys(_ *cli.Context) error {
+	ctx, cancel := installSignals()
+	defer cancel()
+
+	if err := initDB(ctx); err != nil {
+		return err
+	}
+	return asymkey_model.RewriteAllPublicKeys(ctx)
+}