Move commits viewer to the end of details view

Move commits viewer to the end of details view
https://bugs.webkit.org/show_bug.cgi?id=141315

Reviewed by Andreas Kling.

Improved the way list of commits are shown per kling's request.

* public/v2/app.js:
(App.PaneController._updateDetails): Always show the old value even when a single point is selected.

* public/v2/chart-pane.css: Updated the style for the commits viewer.

* public/v2/commits-viewer.js:
(App.CommitsViewerComponent): Added "visible" property to hide the list of commits.
(App.CommitsViewerComponent.actions.toggleVisibility): Added. Toggles "visible" property.

* public/v2/index.html: Updated the template for commits viewer to support "visible" property. Also
moved the commits viewers out of the details tables so that they don't interleave revision data.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@179729 268f45cc-cd09-0410-ab3c-d52691b4dbfc