MDL-38689 behat: New test

According to MDLQA-931, a teacher can
copy an activity
MDL-38689 behat: Allowing more than one selector type argument

Regex's placeholders can not be repeated, if
there are definitions that have more than one
selector type of the same kind it would not
be displayed like that in the steps definitions
list UI
MDL-38689 behat: Steps definitions to compare DOM nodes position inside the DOM