Add options for hiding post and user engagement statistics.

This adds two options to the frontend settings for configuring the display of statistics:

• Enabling "Hide user statistics (e.g. follower counts)" hides: Followers, Following, Number of Statuses, Statuses per Day
• Enabling "Hide post statistics (e.g. favorite counts)" hides: repeat and favourite counts.

It was inspired by someone complaining that UIs shouldn't be following commercial trends designed to increase usage and make social media addictive.

As usual, this is being used on my instance, and can be previewed here: https://catgirl.science/users/test

Before

After

Current problems

• The sidebar user card isn't being refreshed properly when the settings are changed.