API tests to verify basic query functionality (list & props)

* Several tests to verify query with prop=, list=, and generator
* Moved query related tests to query\ dir
* Added a generic ApiTestCase::editPage() to simplify page creation
* Fixed minor warnings complained by jenkins/phpcs

Change-Id: I5e3984d797178ae03f048792c7bac8e6a881aa41
Merge "API tests to verify basic query functionality (list & props)"