Updated PostgreSqlNode

- Allow configuration file templates
- Set log file location as attribute
- Better control of commands used in driver

**Note** Requires #1083 for _processOwner_ flag
Added shared memory and max connections config with sample postgresql.conf
Updated database entity tests

- Changed database entities to implement DatastoreCommon
- Converted tests from Groovy to Java
- Fixed usage of DATASTORE_URL attribute
- Changed localhost PostgreSql tests to use less shared memory
- General tidy up of tests
Tidying up database entities