Grant an add-on five different ways

An add-on can be free, included in a plan, bought by subscription, tried for a few days or owned for life. The account resolves them in order, so a lifetime purchase is never switched off by a webhook or an ended trial. The admin panel shows which way each account holds each add-on, grants a trial or a lifetime access, and removes a gift or an access you granted, unless the account would be left over its quota.