MDL-44620 behat: Automates MDLQA-6

- MDLQA-6: By default, a new course contains a news
forum in which only teachers can post and subscription
is forced
MDL-44620 behat: Automate MDLQA-7

- MDLQA-7: By default, a new course contains a Latest
News block which displays a specific number of recent
discussions from the news forum