Create view single activity page

[bpred754]

Create a page where a single activity is displayed. Users are routed to this screen when they click on a specific activity, click on the 'activity' link inside a flagged activity, and when using the following url structure: /activity/:activityId

This task will also change View Activity to Activities. Below is a list of Augeo end points:

• /activity/:activityId (single activity)
• /activities/ (All activities for the logged in user)
• /activities/:username (all activities for the specified user)
• /community (all activities for all users sorted by the most recent flagged date - this will be introduced in a later task #53)

Since an entire page will be given to a single activity, this may be a good spot to add a comments section.