This version component reflects the "version" of the StaticContent
objects which we cache server-side.  If the layout of those objects
changes between releases, errors occur when loading them from cache.

By using a separate version value, which can be incremented on its own
after a change has been made to the StaticContent class, we can avoid
loading older cached content and in turn take advantage of these changes
faster, without needing to intervene operationally.