Add support for Summing up deque of quantities

[matthias-wende-frequenz]

What's needed?

from frequenz.quantities import Power
from collections import deque

power1 = Power.from_watts(230.0)
power2 = Power.from_watts(240.0)

power_deque = deque([power1, power2])
sum(power_deque)

This code stops with this error TypeError: unsupported operand type(s) for +: 'int' and 'Power'

Proposed solution

The reason is that the sum starts with an integer 0. This we need to implement the __add__ method for quantities that excepts integers.

Use cases

No response

Alternatives and workarounds

No response

Additional context

No response

[matthias-wende-frequenz]

This can be archived by adding a second initialization parameter to the sum, i.e.

total_power = sum(power_deque, Power.zero())