Meza/Setting up a common uploads wiki

With multiple wikis, a ForeignFileRepo (aka "commons wiki") can be useful -- so that you don't have to upload the same image multiple times into each wiki.

This capability is currently being developed and the current configuration notes are as follows:

// Set the English wiki to share images with everyone
$wgForeignFileRepos[] = [
        'class' => 'ForeignDBRepo',
        'name' => 'mainwiki',
        'url' => "$wgServer/mediawiki/{WikiID of the commons wiki}/img_auth.php",
        'directory' => '/opt/data-meza/uploads/{WikiID of the commons wiki}',
        'hashLevels' => 2, // This must be the same for the other family member
        'dbType' => 'mysql',
        'dbServer' => $wgDBservers[0]['host'],
        'dbUser' => $mezaDatabaseUser,
        'dbPassword' => $mezaDatabasePassword,
        'dbFlags' => DBO_DEFAULT,
        'dbName' => 'wiki_{WikiID of the commons wiki}',
        'tablePrefix' => '',
        'hasSharedCache' => false,
        'descBaseUrl' => "$wgServer/mediawiki/{WikiID of the commons wiki}/File:",
        'fetchDescription' => false