The module doesn't work or exist anymore.
I use a lightwight battery icon instead which I add as a service to
start during login.
And I don't need the wifi thingy.
Do not hard code all values, instead configure them within home.nix.
This is more for learning purposes.
But port and allow might also be changed more frequently in general.
home-manager doesn't provide a systemd service itself.
That's why we build one ourself.
That also revealed a change in our directory structure.
The structure is now documented within readme.