[Discussions] Allow for bulk actions in Discussion folder

[DeteesWuber]

Problem statement:

Currently, you have to click on the settings for each discussion to pin it and close it to comments. You also have to click on 'Publish' and 'Subscribe' for each discussion individually. However, these 4 actions would be predisposed to offer corresponding Bulc actions under 'Discussions' to make the work easier.

Proposed solution:

Offer bulc actions in the Discussion folder for the following activities: pin/unpin, close/open for comments, publish/unpublish, subscribe/ unsubscribe. It makes work easier.

User role(s):

admin,instructor,student,ta