made a new Transform which receives Req type paramter

[BaekGeunYoung]

resolves #608

made a new Transform, RTransform, which embeds Req type also.

def effect[Req, Resp](
      io: (Req, ContextIn) => ZIO[Any, ErrorIn, Resp]
  ): (Req, ContextOut) => ZIO[Any, ErrorOut, Resp]

and added a codegen logic which adds a method to transform service using RTransform

[thesamet]

This is especially useful -> this can be used
resposne -> response

[thesamet]

Thanks for sending the PR! The change itself looks good. Can you add:

• a spec similar to EnvSpec (new file please) that demonstrates this change works for all 4 type of RPC methods
• update the docs (docs/context.md) with the new transformation type.

[cipriansofronia]

@BaekGeunYoung any progress on this one?