Support for multiple modules

[eneufeld]

I have a use case where I want to be able multiple modelservers standalone as well as run them as one bis model server.

Currently the modelserver expects to have exactly one module that extends the ModelServerModule.
Also many of the services are singletons. These services cannot be overriden then and need to be unified manually.

I currently see 2 ways of doing it:

• use private modules which only expose the ModelController using the file extension they support as annotation. This might be problematic for glsp integration where we need to handle multiple resources. Unfortunately a private module cannot add to a multibinding directly. There are workarounds but the elements need to be manually retrieved and pushed into the multibinding.
• instead of registring codecs in a map using the format, use a provider that also takes the modeluri into account. This probably solves most of the requirements but some special cases would need to be unified manually or also extracted to multibindings.