Dessia common Road map

This is the change roadmap for dessia common. Once implemented, update CHANGELOG.md

Short term (next month)

Refactorings

workflow: move blocks to submodule
remove barrel imports: dessia_common, dessia_common.workflow
split Dessia Object in equality , serailization, export & displays capabilities

New features

Midterm (6 months)

LongTerm (1 year)