Pantry parsing and functions

> The pantry file uses TOML sections to organize items by storage location:

```toml
[
freezer
]
cranberries = "500%g"
spinach = { bought = "05.05.2024", expire = "05.06.2025", quantity = "1%kg" }

[
fridge
]
milk = { expire = "10.05.2024", quantity = "1%L" }

[
pantry
]
rice = "5%kg"
```