Decide if Entity Framework is to be used

[olebhansen]

Description

Preferably get guiding/inputs. If we can decide in the team; make the decision. Output of this task is an ADR.

Pro:
"better" way of managing entities than hand-crafting.
Reduces codebase

Con/implication:
If deciding, we should plan to convert/modernize our other apps too (in the long term)
Short term there will be many ways for the same pattern
Will need more re-writing than if just taking the code from Altinn2 as it is.

Desicion

We will go for Entity Framework.