Make the article-bottom widget area into an action

[benlk]

Changes

• Replaces the article-bottom widget area call in the single one- and two-column templates with the action largo_post_bottom_widget_area
• Adds new function largo_post_bottom_widget_area to output the article-bottom widget area, hooked on largo_post_bottom_widget_area. (Same name for function and action.)
• Docs in docs/developers/hooksfilters.rst

Why

To make it easier to modify this area.

[benlk]

Demo code for removing this area in a child theme:

/*
 * Remove the Largo default sidebar output.
 */
function rns_largo_remove_article_bottom_sidebar() {
    remove_action( 'largo_post_bottom_widget_area', 'largo_post_bottom_widget_area');
}
add_action( 'init', 'rns_largo_remove_article_bottom_sidebar', 99);