Let install.php detect and inject extensions [2]
For CI, I went with a dirty trick to find extensions and either
wfLoadExtension() or include them. That has since been ported to
Installer::findExtensions() and LocalSettingsGenerator::getText().
The WebInstaller() relies on that to detect extensions and let the user
tick the ones to be installed.
Add --with-extensions to install.php so one can include all extensions
from the command line.
Note: The CliInstaller always wfLoad() any skin it can find.
The original patch
53926d9d was broken and got reverted. This is the
proper one.
Bug: T189567
Change-Id: I41820fce12e01224d64ab711e016835ef4d4febc