[#73] Uploader, downloader structures refactoring

Signed-off-by: Marina Biryukova <m.biryukova@yadro.com>

main.go

@@ -1,17 +0,0 @@
-package main
-
-import (
-	"context"
-	"os/signal"
-	"syscall"
-)
-
-func main() {
-	globalContext, _ := signal.NotifyContext(context.Background(), syscall.SIGINT, syscall.SIGTERM)
-	v := settings()
-	logger, atomicLevel := newLogger(v)
-
-	application := newApp(globalContext, WithLogger(logger, atomicLevel), WithConfig(v))
-	go application.Serve()
-	application.Wait()
-}