Change the modeshape-schematic module to contain only document-related classes

The modeshape-schematic module should be updated so that:

• all Infinispan dependencies are removed
• the package name is changed from org.infinispan to org.modeshape
• still contains the top-level persistence abstractions

The last point is especially important, since these top-level abstractions (e.g. SchematicDB) will serve as the basis for the new persistence SPI.