More PHPDoc fixes, using scrutinizer patches as hints

lib/private/appconfig.php

lib/private/cache.php

lib/private/contactsmanager.php

lib/private/db.php

lib/private/image.php

lib/private/legacy/appconfig.php

lib/private/request.php

lib/private/share/mailnotifications.php

lib/public/contacts/imanager.php

lib/public/iappconfig.php

tests/lib/appframework/routing/RoutingTest.php

tests/lib/dbschema.php