Add method to clean up old analytics tokens
When a user no longer uses a module, the analytics remain forever. This can be particularly annoyed if they're using old versions, because it can seem that old versions are still in use.
It could be good to:
- Have an endpoint to purge analytics for a given analytics token (should this be globally, or for a particular module?)
- Be able to ignore analytics tokens that match a given pattern
Github reference: https://github.com/MatthewJohn/terrareg/issues/59