remove exadmin css themes relate styles.
set box_content_class.
show delete item model info use label-info css class.
add striped style to tables.
add themes plugins.
add exadmin default theme css file.
add change themes js file.
update base.html template, add theme hook tag.
add id attr to top level elements.
top search bar remove inverse style.
show chart use box.
remove not layout style for theme feature.