User profile page: More responsive contribution graph on "Overview"

Problem to solve

With %11.4, we are adding a first iteration of a user profile redesign. The contribution graph now defaults to six months, with a link to the full 12 months graph on the "Activity" tab. There's potential to make the graph on "Overview" more responsive.

Proposal

Let's switch to 12 months (just like on "Activity") if the width allows for it (924px plus horizontal margins).

In the future, an even more responsive approach would be to always show the graph starting from the beginning of a month depending on available width. E. g. on the first attached screen, I might see February and March as well.

Design

The first iteration can be as simple as the example by @wortschi in this issue.

Mobile	Tablet	Desktop

What does success look like, and how can we measure that?

(If no way to measure success, link to an issue that will implement a way to measure this)

References

My default browser size	Large width