[WIP] RESTEasy module now automatically adds @Produces if required

[chkal]

The specification contains the following requirement:

The semantics of controller methods differ slightly from JAX-RS resource methods; [...]. Moreover, the default media type for a response is assumed to be text/html, but otherwise can be declared using @Produces just like in JAX-RS.

This means that if a controller methods doesn't use a @Produces method to define a concrete media type, Ozark must configure the JAX-RS implementation to behave as if the controller has a @Produces("text/html) annotation.

The Jersey module already does this using a special Jersey SPI. For RESTEasy such an SPI did not exists. Therefore I filed RESTEASY-1805 and implemented this feature which is currently under review here.

So if my pull RESTEasy pull request is merged, the SPI will be available in the next RESTEasy 4.0.0 milestone. We could then update our RESTEasy dependency and apply this PR.

[chkal]

A small update on this. According to the RESTEasy team, the new SPI will be included in the 3.6.0.Final release.