Fixed multiple bugs / WP5.0 compatible

【Features added and fixed】
■Added support for WordPress 5.0 (Gutenberg).
■Fixed a bug that the table is displayed even if the D item of the fixed page template 3 is left blank.
■Fixed a bug that the link doesn’t work in the free space of footer PR area.
■Fixed a bug that the link button of plan contents is displayed even if the link text is left blank.
■Fixed the bug that meta description is not output correctly.
■Fixed a bug where the footer SNS setting “Email Address” was not linked correctly.
■Fixed a line break code in some files.

The following are the files that have been modified for this update.
【Corrected files】
inc/seo.php
languages/ja.mo
languages/ja.po
pagebuilder/assets/admin/css/admin.css
pagebuilder/assets/admin/js/admin.js
pagebuilder/assets/admin/js/googlemap.js
pagebuilder/assets/css/googlemap.css
pagebuilder/assets/css/pagebuilder.css
pagebuilder/assets/css/slider.css
pagebuilder/assets/js/googlemap.js
pagebuilder/modules/catchcopy.php
pagebuilder/modules/googlemap.php
pagebuilder/modules/headline.php
pagebuilder/modules/image.php
pagebuilder/modules/simple_table.php
pagebuilder/modules/slider.php
pagebuilder/modules/tab.php
pagebuilder/pagebuilder.php
template-parts/page-type4.php
footer.php
front-page.php
header.php
style.css