Fixes many WPCS errors and warnings
Also:
* Partly removes excessive php opening/closing tags.
* Uses printf for better readability in loop-templates/content-none.php.
* Adds understrap_kses_title() to escape post titles.
* Adds understrap_escape_the_archive_description() to escape the archive description.
* Fixes missing '__' after esc_html in author.php.
* Updates the phpcs.xml to reflect all the changes.
* Updates composer dependencies and scripts.
Add a empty page template with just a header and footer section and a
„naked“ content section in between. The content comes without any
markup so you can add your own markup to the page. Good for landing
pages or other pages which needs to use another markup besides the
default stuff.