Add support of Optional types in BeanParams

While migrating my code from Dropwizard/Jersey to Quarkus/Resteasy, I realized that the support of Optional types is actually partial. Indeed, if we try to inject an optional type into a BeanParam, we end up with an error of type:

RESTEASY003875: Unable to find a constructor that takes a String param or a valueOf() or fromString() method for javax.ws.rs.QueryParam("valueQ1") on java.util.Optional ...