In e19092240 the ability to configure the 2017WTE to be "graduated" out of
beta and available to all. However, for a week of config cut-over, this is
re-using a config switch which previously gated the beta feature, and so
will be immediately available to all users until we put it back under beta
when Ie13215bd is deployed. Oops.
Change-Id: I1bc556849a6eb1e895f03412a9cb78002c8a0aee
Principal code is in includes/*.php with the file named the same as the class it
contains. The maintenance script is moved to maintenance/ for clarity.
Change-Id: Icb4cdffb1bd4716e14f883d667def96671b42992
