Initial addition
Added creation of keyspace

 - Now creates Cassandra keyspace and its various options defined in the
 connectionDetails map using the KeyspaceActionSpecificationFactoryBean.
 - Removed Spring Data Cassandra Factory beans creation methods, the
beans are now settable to allow overriding and are now destroyed on
destroy().
 - GormCassandraSessionFactoryBean moved to separate file.
 - Renamed constants removing cassandra prefix as it is redundant.
 - ConfigUtils.read method inlined as connectiondetails can have non
string values when a ConfigObject is passed in from Groovy.
 - added validation of property Enums.