common: fs_util: Add buffer to string view utility functions

These functions allow to construct a string view from an input buffer, avoiding the copy done by the non string view counterparts. However, callers must be cognizant of the viewed buffer's lifetime to avoid a use-after-free.

src/common/fs/fs_util.h

@@ -37,6 +37,15 @@ concept IsChar = std::same_as<T, char>;
  */
 [[nodiscard]] std::u8string BufferToU8String(std::span<const u8> buffer);
 
+/**
+ * Same as BufferToU8String, but returns a string view of the buffer.
+ *
+ * @param buffer Buffer of bytes
+ *
+ * @returns UTF-8 encoded std::u8string_view.
+ */
+[[nodiscard]] std::u8string_view BufferToU8StringView(std::span<const u8> buffer);
+
 /**
  * Converts a std::u8string or std::u8string_view to a UTF-8 encoded std::string.
  *
@@ -57,6 +66,15 @@ concept IsChar = std::same_as<T, char>;
  */
 [[nodiscard]] std::string BufferToUTF8String(std::span<const u8> buffer);
 
+/**
+ * Same as BufferToUTF8String, but returns a string view of the buffer.
+ *
+ * @param buffer Buffer of bytes
+ *
+ * @returns UTF-8 encoded std::string_view.
+ */
+[[nodiscard]] std::string_view BufferToUTF8StringView(std::span<const u8> buffer);
+
 /**
  * Converts a filesystem path to a UTF-8 encoded std::string.
  *