Add structured compose printer

[olehan]

Motivation

Structured Key-Value printer is twice slower than the Template or Base printers, so I have an idea that will fix the problem and get a better logging experience.

Description

Expected function type:

type PrinterComposer interface {
    Interface(key string, value interface{}) PrinterComposer
    String(key string, value string) PrinterComposer
    Int(key string, value int64) PrinterComposer
    Bool(key string, value bool) PrinterComposer
    // And so on...

    // A function that is going to Write to the Writer from a linked buffer.
    Flush() PrinterComposer
}

type PrintSC = func(message string) PrinterComposer

Expected usage:

logger.PrintSC("user info:").
    String("name", "My").
    Int("age", int64(32)).
    Bool("male", true).
    Flush()

The idea is to get type-safe and fast structured logging.