Backend integration code for flagging priority questions for faculty issue #12 + NPM test code coverage fix

[tjpatel04]

Deleted notifications.js initial changes feature from sprint 1 to fix code coverage and testing to successfully run npm test. Decided to focus on different feature implementation.

Changed topics/create.js, edit.js, posts/create.js, and added priorityflag.js file to implement the backend feature code for issue #12. Feature flags any post with certain priority and assigns a color (green,orange,red) with red being the highest priority to a students post for increased faculty visibility.

[Sharkesh111]

I left a comment about the functionality of how we assign priority levels to a comment that has multiple priority levels in it. This is just a small edge case to consider, but other than that your code looks great!

[Sharkesh111]

With this code, the way you are looping through the priority map from low to high, it makes it so that in the edge case where the user enters high priority and low priority in the same comment, the comment will be flagged as low priority due to the order of the loop.

We may want the comment to be flagged as the highest priority mentioned in the comment.

In this case, just reverse the order you initialize PRIORITY_MAP from ascending order by priority level to descending order.

[Caryzxy]

This looks good, should have no conficts with other functions in other PR