v1.5.1 — the waiting list asks for the license domain

The LibreDB Platform waiting list now asks for the two things a license is issued for: the organization, as it should appear on the license, and the one domain Platform will run on.

The domain field accepts a domain name only, such as libredb-platform.example.com, and its hint points to the installer setting that takes the same value. Requests now arrive with everything needed to issue a key, so nobody has to send a second email to ask for the domain.