Subprocess returns stdout as bytes instead of str nowadays, so I
addressed it in a quick and dirty way.
The extra return in healthcheck function is added there to stop the app
from complaining about it and also because I discovered that the
solution for tracking printer status here is essentially hardcoded for
English, while my local test environment outputs lpstat logs
in Ukrainian.
Due to old pangocairo bindings seemingly not being updated anymore
I resorted to using cffi-based bindings for now.
Current problems with pango and pangocairo bindings is that they are
incomplete, and it seems like outside HTML parsing there are some broken
things about font rendering, which I need to deal with. I might look
into rebuilding this functionality using something else, maybe Pillow.
Health check was disabled for now so I can focus on image rendering.