Add new views and styles for music application

- Created new CSS files for styling the application, including home.css and style.css.
- Implemented 403 and 404 error views with appropriate messages and navigation.
- Developed a dump view to display deleted elements with restoration options.
- Enhanced home view to include music search functionality and display results.
- Added listplay view for managing music playlists, including creation and deletion options.
- Implemented loadmusic view for uploading new music with necessary fields.
- Created login and register views for user authentication.
- Developed sound view to display individual music tracks with playback controls and options for liking and deleting.
- Updated menu view to include navigation links based on user authentication status.

view/404.view.php

@@ -0,0 +1,11 @@
+<div class="body" style="background-color: #212529;">
+    <?php include $views['menu'] ?>
+    <br><br>
+    <center>
+        <img class="box-10" src="<?= $assets['IMAGE']['FILE_DIR']['404'] ?>" alt="">
+        <br><br>
+        <h1 class="text-muted">P&aacute;gina no encontrada!</h1>
+        <br>
+        <a href="./?view=home" class="btn btn-primary"><i class="fas fa-arrow-left"></i> volver</a>
+    </center>
+</div>