LINE Accessible License Server

Set environment variable ADMIN_TOKEN, then use these APIs:

GET  /api/admin/licenses
POST /api/admin/licenses   {"label":"user name","maxMachines":1,"expiresAt":""}
POST /api/admin/revoke     {"serial":"LA-...."}
POST /api/activate         {"serial":"LA-....","hardwareId":"...","app":"line-accessible"}