add generic wrapper function for all the things - `wds_do_page_builder()`

[jazzsequence]

this would be different than wds_page_builder_load_parts but could potentially use that function. usage would look something like this:

wds_do_page_builder( array(
     'section',        // wrapper type, e.g. <div>, <aside>, whatever
     'part-container', // wrapper class or classes
     'layout-name',    // optional, the layout to load or whatever the default is
) ); 

[jazzsequence]

maybe find a better name.

[jazzsequence]

new function is wds_page_builder_wrap

[jazzsequence]

tested, refactored, tested a lot more, working now. :boom: