=== Description
`performer.is_temp` is a contextual attribute that is already included at the common schema (https://schema.wikimedia.org/repositories//secondary/jsonschema/fragment/analytics/product_metrics/common/current.yaml). It was also included to the Java MP library but there is nothing about it neither for the JS and PHP ones nor the `EventLogging` extension.
This field must be added as a contextual attribute for the JS and PHP MP libraries and for the `EventLogging` extension.
=== Acceptance criteria
[v] `performer.is_temp` has been added to the JS Metrics Platform library
[v] `performer.is_temp` has been added to the PHP Metrics Platform library
[] `performer.is_temp` has been added to the `EventLogging` extension
=== Required
[v] Unit/Integration tests
[] Documentation
[] Passed QA