Config management diff: Rename "Old" and "New" to something more meaningful

When viewing a diff on the configuration management synchronization page, it has a side for "Old" and one for "New".

However, this makes little sense, considering either version can be old or new, since:

• If things have been changed in active, then they are the new version and the staging directory is the old version.
• But if you are deploying changes, then the staging is the new version and the active has the old version.

We should probably change the wording from this to "Active" and "Staging".