feat(ns): improve optimization flags and add namespaces (#1261)

Signed-off-by: k4yt3x <i@k4yt3x.com>

include/libvideo2x/logutils.h

@@ -0,0 +1,28 @@
+#pragma once
+
+#include <optional>
+
+#include "fsutils.h"
+
+namespace video2x {
+namespace logutils {
+
+enum class Video2xLogLevel {
+    Unknown,
+    Trace,
+    Debug,
+    Info,
+    Warning,
+    Error,
+    Critical,
+    Off
+};
+
+void set_log_level(Video2xLogLevel log_level);
+
+std::optional<Video2xLogLevel> find_log_level_by_name(
+    const fsutils::StringType &log_level_name
+);
+
+}  // namespace logutils
+}  // namespace video2x