(bug 61691) Delay loading editor javascript until after initial page load

This delays the loading of ext.flow.editor dependency, which is not immediately
needed, this speeding up pageload.

The editor module will be loaded after 20 seconds (so that when we need it, we
don't have to wait for it to be loaded), or immediately (should it be needed
earlier anyway)

Bug: 61691
Change-Id: I9ae88921b678419a1e18fe5e421638e823151fb7
Merge "(bug 61691) Delay loading editor javascript until after initial page load"