Consider removing the `serializers` module

[amonsosanz]

This issue comes from this and this discussions of a PR.

We currently have a module named serializers which contains many parsers (and serializers).

I'm not sure we need this generic serializers module tbh... I'd rather move these serializers next to their respective parsers in the corresponding adapter.

Adapter modules are properly interface-segmented and can hold both the parsers and serializers for each interface (bridge-api, browser, local storage, etc).

We can group together each parser/serializer pair or separate them into blocks using comments:

// parsers

...

// serializers

...