Refactoring service layer. Part 1 (#25945)

Refactoring some functionality out of the service package so it can be
reused by a different service package.
- auth middleware
- logging errors

No functional changes.

server/service/debug_handler.go

@@ -12,6 +12,7 @@ import (
 	"github.com/fleetdm/fleet/v4/server/contexts/token"
 	"github.com/fleetdm/fleet/v4/server/errorstore"
 	"github.com/fleetdm/fleet/v4/server/fleet"
+	"github.com/fleetdm/fleet/v4/server/service/middleware/auth"
 
 	kithttp "github.com/go-kit/kit/transport/http"
 	kitlog "github.com/go-kit/log"
@@ -32,7 +33,7 @@ func (m *debugAuthenticationMiddleware) Middleware(next http.Handler) http.Handl
 			return
 		}
 		ctx := token.NewContext(context.Background(), bearer)
-		v, err := authViewer(ctx, string(bearer), m.service)
+		v, err := auth.AuthViewer(ctx, string(bearer), m.service)
 		if err != nil {
 			http.Error(w, "Invalid authentication", http.StatusUnauthorized)
 			return