Resteasy Reactive support for multivalued parameters

[preokane]

Description

I've been trying to get Resteasy Reactive to parse arrays of values in my URLs in the form of comma separated values rather than '&' separated values.
e.g. ?array=item1,item2,item3 rather than ?array=item1&array=item2&array=item3

This feature is available in the Resteasy classic extension through the usage of the @Separator annotation and the MultiValuedParamConverterProvider which comes included in resteasy-core and seems to be registered by default.

It would look something like:

@GET
public String hello(@QueryParam("foo") @Separator(",") List<String> foo) {}

It would be nice to have a similar way to do this for the Resteasy reactive extension.

Implementation ideas

Possibly by including these providers which are used by default in the Resteasy classic extension.

[quarkus-bot]

/cc @FroMage, @geoand, @stuartwdouglas