Inclusion of rename organization api (#33303)

This adds an endpoint (`/orgs/{org}/rename`) to rename organizations.

I've modeled the endpoint using the rename user endpoint --
`/admin/users/{username}/rename` -- as base.

It is the 1st time I wrote a new API endpoint (I've tried to follow the
rename users endpoint code while writing it). So feel free to ping me if
there is something wrong or missing.

Resolves #32995

---------

Signed-off-by: Bruno Sofiato <bruno.sofiato@gmail.com>
Co-authored-by: delvh <dev.lh@web.de>
Co-authored-by: wxiaoguang <wxiaoguang@gmail.com>

modules/structs/org.go

@@ -57,3 +57,12 @@ type EditOrgOption struct {
 	Visibility                string `json:"visibility" binding:"In(,public,limited,private)"`
 	RepoAdminChangeTeamAccess *bool  `json:"repo_admin_change_team_access"`
 }
+
+// RenameOrgOption options when renaming an organization
+type RenameOrgOption struct {
+	// New username for this org. This name cannot be in use yet by any other user.
+	//
+	// required: true
+	// unique: true
+	NewName string `json:"new_name" binding:"Required"`
+}