* Remove chat and survey plugins from the standard plugins
* Remove all related tables and settings from both plugins
using upgrade.
* Remove temporary admin notification (MDL-82297) and strings.
* PHP Unit:
- Remove chat and survey as a sample module for unit testing
replacing it with assignment module when possible (if not page).
- Remove chat and survey from bulk update test
* Behat: Remove chat and survey behat tests
Sara Arjona