[PDI-11946] Carte falls back to default repo

When executing a tranformation, carte may not be passed accurate paramters to connect to a repository.
Allow execution to continue with a default preconfigured repository.

http://jira.pentaho.com/browse/PDI-11946

Forward-port of http://jira.pentaho.com/browse/SP-1229
[PDI-11946][TEST] Refactoring and testing

Testing and method extraction of TransExecutionConfiguration, connecting to a repository

http://jira.pentaho.com/browse/PDI-11946
Merge pull request #500 from hudak/pdi-11946

[PDI-11946] Carte falls back to default repo