Bundle not working with Symfony version prior to 3.3

[hknezevic]

Installing the package via composer passes because there is no require statement on the symfony version, only the ezsystems/ezpublish-kernel.

However, some compiler passes, which are enabled by default, call the Definition method setArgument(), which was added in the Symfony 3.3 and not available in the prior Symfony versions:

https://github.com/netgen/ezplatform-search-extra/blob/master/lib/Container/Compiler/FieldType/RichTextIndexablePass.php#L34

https://github.com/netgen/ezplatform-search-extra/blob/master/lib/Container/Compiler/FieldType/XmlTextIndexablePass.php#L32

https://github.com/netgen/ezplatform-search-extra/blob/master/lib/Container/Compiler/FieldTypeRegistryPass.php#L29

If I manually disable these compiler passes, the rest of the features work nicely, as far as I could tell.

It would be nice if we somehow managed to make this compatible with the Symfony 2.8-3.3, so that we don't lock out the possibility of using this package on the older version of eZ prior to 6.12.

I guess something like this would do (e.g. for the FieldTypeRegistryPass):

if (count($fieldTypeRegistry->getArguments()) > 0) {
    $fieldTypeRegistry->replaceArgument(0, $fieldTypeRegistryClass);
}
else{
    $fieldTypeRegistry->addArgument($fieldTypeRegistryClass);
}

If you agree with this approach, I will open a PR. Otherwise we need to lock out the symfony version in the composer.json.

cc @MarioBlazek @emodric @pspanja