Provide valid license key via env var

[michael]

Simple setup that exposes license key via /license

E.g. PERSONAL-02342-812392-0238420823993-2339234

[michael]

potentially render something like a "UNLICENSED | Editable" batch in the footer when license key is not set. And then maybe we could detect valid license keys by how they are structured but super simple check. Jus so that you can't set LICENSE_KEY=foo and the warning goes away