Work around WebKitGTK deprecation of shared-secondary process model
Per the release notes for WebKitGTK 2.25.92, the single process models have been deprecated. We need to set the WEBKIT_USE_SINGLE_WEB_PROCESS
for 3.34 to avoid the memory blowout that would entail, then remove that and switch to constructing WebViews using the related view model to avoid this in 3.36.