*SEO Metatag Info Plugin in the standard distribution*
- includes all languages FlatPress currently supports as standard (translation via Deepl).
- Content customized texts incl. placeholder as example.
- With own hook in entry- and statictemplate, because otherwise the tag plugin is also shown when creating static pages; which is not supposed to be
Updated calls to current Smarty API (register_function()/register_modifier()/register_block() -> registerPlugin(); assign_by_ref() -> assignByRef()).
Fixed file includes in templates with quotes.
Removed SmartyValidate.class.php includes.
Still work in progress as some errors still appear!
