Render the git graph on the server (#12333)

Rendering the git graph on the server means that we can properly track flows and switch from the Canvas implementation to a SVG implementation.

* This implementation provides a 16 limited color selection
* The uniqued color numbers are also provided
* And there is also a monochrome version
*In addition is a hover highlight that allows users to highlight commits on the same flow.

Closes #12209

Signed-off-by: Andrew Thornton art27@cantab.net
Co-authored-by: silverwind <me@silverwind.io>

web_src/less/_repository.less

@@ -3082,11 +3082,3 @@ tbody.commit-list {
         }
     }
 }
-
-#git-graph-container {
-    display: none;
-}
-
-#git-graph-container.in {
-    display: block;
-}