Fixes #880: Integrate JAXRS-Multipart extension

[gastaldi]

Fixes #880

[gsmet]

Hmm, is there any value in this extension? I mean just adding the dependency would be sufficient, wouldn't it?

Wondering if multipart is sufficiently important that we need to expose it as an extension. I don't think we want to create an extension for each JAX-RS provider.

[gastaldi]

@gsmet I copied from the jaxrs-json extension, which falls in the same category.

Otherwise you'd need to add the dependency to resteasy-multipart-provider with the same supported RESTEasy version (and with the proper exclusions), which I am not sure is available when building the project.

[gsmet]

Yes, we did that for JSON because it was the most common use case. Not sure it's worth doing the same for multipart.

We could add it to the bom to mandate the right version.

[gastaldi]

I'm fine with whatever strategy you guys choose 😄 I just want to make my app work 😉

[gastaldi]

@gsmet WDYT about merging this PR and revisiting the strategy for using different providers in a separate PR?

[stuartwdouglas]

This really should just be an entry in the bom