Add area_per_building_residence_equivalent attribute to ETLocal

[kndehaan]

Description

This PR adds the area_per_building_residence_equivalent attribute to ETLocal, which makes it an editable attribute for ETLocal datasets. The ETLocal datasets currently have the value inherited from the parent dataset. Therefore, there's no need for dataset migrations.

Goes with quintel/etsource#3369

Type of change

• Bug fix
• New feature
• Enhancement
• Documentation

Checklist

• I have tested these changes
• I have updated documentation as needed
• I have tagged the relevant people for review

Related Issues

Closes #650

[mabijkerk]

The reason why we sometimes get "empty" commits may be because those values come from the parent dataset without a migration. What do you think @kndehaan, would it be nicer to add a data migration? I don't fully get how the values are in the database without a migration..

Additionally, we can add a description what this attribute entails, technically we do this for "Roof surface suitable for solar PV" as well:

[kndehaan]

What do you think @kndehaan, would it be nicer to add a data migration? I don't fully get how the values are in the database without a migration..

Aha, then it would be nicer to add a migration, especially for the Dutch datasets where we've based the typical area on a data source. I guess we don't know the source for the European datasets, but could use something general like "Quintel assumption".

Additionally, we can add a description what this attribute entails, technically we do this for "Roof surface suitable for solar PV" as well

I forgot that we have this option, but I'm definitely in favor of adding a description to this attribute.

I will pick bot of these thing up. TODO:

• Create dataset migration mentioning the data source
• Add description to area_per_building_residence_equivalent attribute

[kndehaan]

This PR is ready for final review @mabijkerk . Along the way, I found that the value for GM1979_eemsdelta on ETSource is incorrect and updated this in this PR.

Note that I intentionally added PV27_2022 to the migration file of countries since it has the same value and commit message as the other countries (since this dataset still has nl2019 as parent).