EZP-22617: Implement ISBN FieldType
Fix EZP-22617: Added tests (unit & integration)
CS
Fixed for unit tests
Fix EZP-22617: Use get function on fieldDefinition as assumed by tests
Fix EZP-22617: Add API integration test for ISBN and fix missing parts
Fix EZP-22617: Add Solr indexing config + cs
Fix EZP-22617: Move validation, make strict and remove left overs

Fixes review remarks.

In restrospect this field type should have been based on TextLine or
similar FielType, most of the issues with getting this to work properly
can be attributed to the fact that it was copied from Country which has
a different data structure and different validation needs.
Fix EZP-22617: Add ISBN setting block in fielddefinition_settings.html.twig
Merge pull request #852 from ezsystems/ezp22617

EZP-22617: Implemented ISBN Field Type