Contributors: Exclude self-reviews from the dashboard

[ayshushus]

Fix #2627

• The counts still don't equal the number of strings a link returns.
• The timeline counts ActionLog rows while the translate view lists entities.
• In full-year mode, every month row links to the whole period.
• Badges still count explicit self reviews.
• Actions on disabled entities (and obselete projects) no longer count.
• Exclusion on review_time is to avoid "No results" explicitly from self-reviews. This still doesn't fix the first point.

Edit:

• There are many instances of "No results" for a variety of strings that this PR cannot fix.
• The review dates for above strings are set to NULL so they are not linked to self-reviewed cases.
• There are additional cases with ambiguity which are seen from fixing the full-year mode bug (point 3 from above).