Another serialization topic, reduced scope

[Jesse Phillips]

https://youtu.be/Y-cgh-rwoC8

I was watching Steven's 2019 talk. I'd like to put together a DIP 
to specify a collection of attributes which target this very 
common pattern of marking up structure. We see it in c# and Java 
at runtime, and we see it with different D libraries.

Adding and replacing serialization to the standard library has 
had its delays due to expectations of how serialization should be 
designed.

I think it is clear that attributes on structures is a common 
approach placed on top of the actual implementation.

Phobos updates are not traditionally going through a DIP, but I 
think this is the right avenue for review.

We see similar attributes used in things like argument parsing. 
But here is a short list of what I am thinking from an attribute 
list.

@ignore
@optional
@name("field")

Seeing this work through will be hard with a 3y and 3m old, but I 
feel this is the type of library support std can provide even 
with the benefits of dub.

Destroy.