datasource: Discuss meaning of bool field

[mauriciovasquezbernal]

Fields can be booleans, however the exact meaning of this field is not clear. There are two different options:

1. Bool() == false means all bytes are set to 0 (implemented in 11bf3b6)
2. Bool() == false means the first byte is set to (changed in 78a0153)

There was some discussion on #2796 we we never reached a full agreement and decided to move forward with the PR to avoid blocking others. However we need to be sure we're all aligned on this.

cc @flyth

@alban do you have any opinions on this one?