Do not track if DNT is enabled
Add unique visits data to usage ping

Track visit to contribution analytics page

Introduce enum for target_id encoding

Track unique visits to analytics pages

The list of pages to track is in the MR
description

Add a count for any analytics page visit

Expire cookie in 24 months

Refactor the method tracking unique visits

To make it more succint in controllers and
more readable

Add NOT NULL constraint to last_visited_at column

Add a feature flag

Track only if user is signed in

Refactor tests by using shared examples

Use GL batch count for counting visits

Use Redis instead of Postgres

Implement unique visit tracking with
Redis HyperLogLog

Do not track visit if DNT in enabled

And let the user to opt-out

Add the unique visits data to the usage ping

Add new statistics to usage ping documentation

Move unique visits out of service class

Change changelog merge request number