Please, use new {Source,}Pos types

[Anton-Latukha]

A continuation/aggregate of the:

• Initial idea Please, use other/create new {SourcePos, Pos} datatypes #940
• Allow faster parsing: Faster parsing by changing source location representation #746

Expr.Types has instance {Serialize, Hashable, Binary, ToJSON, FromJSON} {Source,}Pos orphan modules (10 instances), which not really can be uploadated to megaparsec.

The classical minimalistic solution is to create new type abstraction, which allows defining instances locally.

So it may be done in several stages, but we at once can thing about new design of the positioning.