ExtendedRuntime project doesn't respect the user naming policies

[dvojtise]

curently the projet that contains the extended metamodel runtime code use the following pattern <MetamodelName>ExtendedRuntime for the project

however, such project usually use a more complex naming scheme with for example org.company ...

We need to use a better default search location which would try to mimic the user schema. In addition, we need a means to let the user specify where this runtime is located. (in order to customise it if the default schema doesn't suit the user's need)