ui: Switch to HTML5 doctype and fix issues

ui: Switch to HTML5 doctype and fix issues

A few common things:

- Remove the 'role' attribute of <nav>
- Don't use the self closing syntax ('/>') on non void elements
- Don't use the language attribution in <script>
- Remove spurious attributes
- The 'check' attribute of <input> doesn't take any value

Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>
Acked-by: Stephen Finucane <stephen.finucane@intel.com>