Update docs menu ordering to be consistent with other platforms

[jskeet]

In all platforms other than Java, .NET is at the top. For instance, Python:

Java has it at the bottom:

In order for this to feel like a single menu just changing the page, the order shouldn't change.

[jgeewax]

And to avoid issues like this, we should try to move to the consolidated site code (gcloud-common/site)

[mziccard]

This was fixed in #1184 and #1182.

And to avoid issues like this, we should try to move to the consolidated site code (gcloud-common/site)

Is there a way I can start depending the app in gcloud-common/site without switching to the json doc format (yet)? Can I configure the manifest.json so that Read the docs still points to our javadoc?