MDL-37046 behat: Use behat test env

Moving from phpunit test environment
to a specific behat test environment
MDL-36269 phpunit Adding more data generators
MDL-36269 behat Adding general use steps definitions
MDL-36269 behat Steps definitions for data generation
MDL-36269 auth Adding basic auth steps definitions and acceptance tests for them
MDL-36269 tool_behat Adding JS hook to detect selenium status
MDL-36269 behat Adding BeforeSuite method

With moodle codebase initialisation
MDL-36269 behat Adding general use steps definitions
MDL-36269 behat Adding extra checking when resetting data
MDL-36269 behat Setters for default and editor form fields
MDL-36269 moodleforms Forms-related steps definitions
MDL-36269 course Add activities steps definitions
MDL-36269 tool_behat Adding new feature
MDL-36269 navigation Solving problem expanding high level tree nodes
MDL-36269 blocks Add blocks feature + step definition
MDL-36269 behat Using only required upstream steps

We need control over the whole set of available steps
to standarize the format and clean the UI for non-technical
users
MDL-36269 tool_behat New test for the behat admin tool
MDL-36269 behat Standarization of steps regex
MDL-36269 behat PHP server must be running
MDL-36269 behat Moving to behat test site