Allow to configure a bigger number of commits loaded by default

[Romain-Geissler-1A]

Is your feature request related to a problem? Please describe.
I am coming from a BitBucket instance, and miss a lot the commit graph view. In BitBucket, the commit graph view was bigger by default, it seems this extension uses only 10 commits at the beginning while I would have had expected more 30 or 50 commits to be more "useful" according to me.

Describe the solution you'd like

• Either an increased default first value of loaded commits: 30 or 50 as the default.
• Either a way to customize the extension to increase the number of loaded commits from 10 to 30, 50 or more.