Check cpp_info propagation to dependencies based on traits in *Deps generators

[AbrilRBS]

Some generators currently filter information more than others based on the traits of the requirement, we should check that:

• What we're filtering in each makes sense/is correct
• That we're not missing anything obvious
• Could we make them identical for every generator?

[AbrilRBS]

Partial work done in 2.20, planning on moving this further for 2.21, which might improve further generators/aggregate the logic in a single common place