[FEAT]: Support for QueryBuilder.quantity to take a units.Quantity instance

### ❓ Problem statement

Currently `.quantity()` takes a value and unit pair. Would be nice to be able to use a `units.Quantity` here or maybe even use binary operators to support it directly in the builder, though I don't remember enough of the binary operator protocol to say this is possible inside of this package to override (I don't really think it would be)

### 💡 Proposed solution

```py
b = CfxExpressionBuilder()
expr = b.reductions.area_ave(
expression=V.TEMPERATURE, location="inlet"
) + b.quantity(1 * K) # or better just + 1 * K
assert str(expr) == "(areaAve(Temperature)@inlet + 1 [K])"
```

### 🔀 Alternatives considered

_No response_

### 📌 Additional context

_No response_