All records which are not saved or useable are now skipped.
Some records were converted but could not be stored, e.g. because no
localization was configured for that table.
This should bring small performance improvement and also align import
log with actually imported (converted) records.
Logging is added as well, only debug level, to allow developer and
integrator to analyse why some records are skipped.
Ignore some errors which don't actually exist.
We already check type of entity, and logger is always injected.
- Removed individual converters for TYPO3.
Conversion is now handled in a single converter.
- The new converter will import necessary dependencies upfront, e.g.
town or organisation.
- Move import state into extra class.
Relates: #34
