Improve presentation of contribution analytics on group page

The graph on the contribution analytics does not properly display many contributors. The presentation on this page could also improve.

Proposed:

Changes to be introduced:

• change charts to full-width
• min-width of the chart bars should be 20px
• max-width of the chart bars should be 50px
• the charts can be scrolled horizontally (by dragging) when all of the bars at their min-width don't fit
• the possibility of horizontal scrolling should be indicated like this
• update the visual style to match recent chart redesigns
• introduce segmented control for the time period
• update the tooltips (on hover) to match the design pattern
• change default sort order to 'by the action in question decreasing'
• the max-width for the full names in the x axis is 120px, the name gets truncated if longer than that (use proper ellipsis symbol '…')
• change the description on top left to 'Showing contributors from [start date] to [end date]'

Chart scrolling

When scrolling to the right, the shadow should appear on the left-side of the chart. And when reaching the far end of any side, the shadow should disappear from that side.

Indicating that there's more content on the right and that the chart can be scrolled:

Scroll right

Scroll left

Scroll either side

Current: