feat: unify common traits

[wilhelmagren]

Now that we have core functionality implemented for flf to parquet and are looking at supporting other sources and targets, we need to define the traits of e.g. Builder, Converter Writer, Slicer, Schema etc.

What needs to be done?:

• Builder trait needs to be defined.
• Converter trait needs to be defined.
• evolution-parser module needs rewrite to support parsing and trimming data other than flf.
• Schema trait needs to be defined.
• Slicer trait needs to be defined.
• add Csv target to the evolution-targets module.
• Go over the Writer trait and verify that its definition makes sense.

[wilhelmagren]

I think we need to rethink how to structure these different modules and potential traits... Also, I think that if we are to work with reading different types of data sources, we need an intermediate representation of the data.