Include total hours and date user joined to the user page

[oahray]

Currently, we can see the awesome charts on the user page, but we have to hover over charts and do some mental calculation to know the total hours that the user has spent in the given period specified by the filter.

Also, it would be nice if we can easily see when a user joined Hours.

I'd raise a small PR for these changes shortly.

[dkhgh]

sounds good, please include tests for the new stuff 👍