add the possibility to to define the name of the project that will host the generated Melange Language Runtime

[dvojtise]

Currently the Melange Language Runtime is generated in a project whose name is directly inferred from the full qualified name of the language in the melange file.

In some case it would be useful to be able to use a specific name for the hosting project. (in order to make clear that the project has been generated, or that it contains a MelangeLanguageRuntime for example)

In addition, this should also allow to generate this directly in the same project that host the melange file itself, so everything related to this language is in the same project (model type, adapters, and language runtime)