🎉 feat: implement master layout system with SectionManager and custom layout support

[harunollyo]

With this PR we can now

From controller

public function account_page(Request $request)
{
     return view( 'site.account.dashboard' )->layout( 'account-layout' )
}

// account-layout.php
<?php Template::get_header(); ?>
<div>Sidebar</div>
<div><?php render_section( 'content' ); ?></div>
<?php Template::get_footer(); ?>

// dashboard.php
start_section( 'content' );
echo "This is dashboard";
end_section();