mD

Correct deprecated methods in PHP7.4 (#1079)

12

* `runtime/lib/query/Join.php` `implode()` was used against the definition (wrong PHP documentation * `runtime/lib/query/ModelCriteria.php` `count()` was used on non-countable variable (non-array)

**Issue**: `runtime/lib/query/Join.php:540` gives warnings in PHP7.4 The reason is that the `implode()` method is used against standard: ```$joinCondition = sprintf('(%s)', implode($conditions, ' AND '));``` For historical reasons, the implode() function...