Fixes#2807
* Update libs
* Refactor the logging system to match Aura SQL 3
* Bump PHPUnit version
* Downgrade spatie/array-to-xml to 2.15
* Upgrade expectations to PHPUnit 8+
* Drop PHPUnit 6 support
Co-authored-by: Léo Colombaro <git@colombaro.fr>
* cleanup geo functions
* add support for CloudFlare's Country GEO header without the need for IP resolution and database
* ensure flag URL always returns a string, instead of false on failure as the result is always used as a string (without validation)
* add helper yours_get_db() so we don't need to use "global $ydb" throughout and it ensures that ydb is always initialised correctly and hasn't ever been changed to something incompatible.
* simplify debug get log
* tidy up code and phpdocs for functions-plugins
* cleanup & phpdocs for parts of functions.php
Co-authored-by: ྅༻ Ǭɀħ ༄༆ཉ <ozh@ozh.org>
