Enabled assignment of content/learning objectives to learners by coaches

[jamalex]

(From call with Team4Tech today, and previously discussed, but not tracked on GitHub)

The content recommendation system helps learners discover content, but we've talked about having ways for coaches to recommend/assign content to their learners/groups, and have that feed into the content recommendations. This issue is a placeholder for discussing what that might look like.

[anuragkanungo]

@jamalex, Thanks for opening the issue. As per the feedback from teachers in Nalanda Project, we are in utmost requirement of a way in which they can recommend/assign content to the learner groups. Not sure, whether it can be done in 0.14 or not, but something worth of importance.