Add unique count metrics for Wiki events

...unt_distinct_project_id_from_create_wiki_page_monthly.yml

...unt_distinct_project_id_from_delete_wiki_page_monthly.yml

...unt_distinct_project_id_from_update_wiki_page_monthly.yml

...count_distinct_project_id_from_view_wiki_page_monthly.yml

.../count_distinct_user_id_from_create_wiki_page_monthly.yml

.../count_distinct_user_id_from_delete_wiki_page_monthly.yml

.../count_distinct_user_id_from_update_wiki_page_monthly.yml

...8d/count_distinct_user_id_from_view_wiki_page_monthly.yml

...ount_distinct_project_id_from_create_wiki_page_weekly.yml

...ount_distinct_project_id_from_delete_wiki_page_weekly.yml

...ount_distinct_project_id_from_update_wiki_page_weekly.yml

.../count_distinct_project_id_from_view_wiki_page_weekly.yml

...d/count_distinct_user_id_from_create_wiki_page_weekly.yml

...d/count_distinct_user_id_from_delete_wiki_page_weekly.yml

...d/count_distinct_user_id_from_update_wiki_page_weekly.yml

..._7d/count_distinct_user_id_from_view_wiki_page_weekly.yml

..._examples/controllers/internal_event_tracking_examples.rb