Allow to use an arbitrary PE impact factor

[demeringo]

Problem

By default Boavizta API (and cloud scanner) uses a PE impact factor (electricity mix) by country.

In some cases we may be able to use a more precise figure (i.e. DC specific source of energy).
Furthermore, Boavizta API may allow (to be verified) to pass custom factors with a query.

Solution

Investigate if we can overide this factor in cloud scanner so that it is used by Boavizta API in the calculation.

Alternatives

Additional context or elements