Updated Items Grid, Carousel and Carousel Simple Macros moved into its own template and redesigned

As per title, I've moved the 3 "Items" macros items_grid, items_carousel and items_carousel_simple out of the xa_sc_index_macros template into their own template xa_sc_widget_items_macros (since these are only used in Widgets).

Note: If you have done ANY customization(s) to these Macros, you will need to SAVE those before upgrading and reapply them in the new template (otherwise they will be LOST).

I've completely redesigned the items_grid macro to get rid of all the duplicate code. It is much more streamline now and consists of several sub macros that are called instead of REPEATING blocks of the same code over and over and over. THIS IS BEING DONE IN ALL OF MY ADDONS for the Content Type Grid Block Layout type (only addons that use this particular layout type).

Note: The items_carousel macro and items_carousel_simple are also slightly redesigned and ALSO uses some of the sub macros.

Getting a few templates more compliant with DRY (do not repeat yourself).