Far more easier to remember

It's easier to understand more optimal for managing static pages.

See  #564

Add SECURITY.md also fix unexpected behavior with tags in number. See #614

Add last modified time variable (eg. $p->lastMod). Add fallback just in case the tags count not the same.

Publish a post with future date or time, it will go into scheduled posts.

Remove deprecated warning for PHP 8.x

replacing text with new added key values from language files (;errors - Invalid_Error)

This reverts commit 9d25d5e49d.

Allow to use tag like C++ and double check for the same tag slug.

PHP 8 compatibility

We will change the date format in one go later.

system/htmly.php
- Loads language files from folder lang/
- Sets language settings for date and time format
system/includes/dispatch.php
- function i18n() returns translated strings