Gotenberg/PDF gen implementation (#4574)

* Gotenberg/PDF gen implementation

* Security, PDF type enum, propagate client

* chore: query cache, clippy, fmt

* clippy fixes + tombi

* Update env example, add GOTENBERG_CALLBACK_URL

* Remove test code

* Fix .env, docker-compose

* Update purpose of payment

* Add internal networking guards to gotenberg webhooks

* Fix error

* Fix lint

apps/labrinth/src/util/mod.rs

@@ -9,6 +9,7 @@ pub mod date;
 pub mod env;
 pub mod error;
 pub mod ext;
+pub mod gotenberg;
 pub mod guards;
 pub mod img;
 pub mod ip;