EZP-23053: Provide more information on FieldType not found exceptions

From [issue](https://jira.ez.no/browse/EZP-23053):
In same way as Limitation Not found exception was improved in #899, provide new exception for missing FieldTypes with more helpful information on how to resolve the issue.
hmm, that is true, however this is a separate issue the original comment and it is already an issue for code above the API (if thrown by Repository as opposed to Persistence/Legacy).

If we want to fix this (guess we should) we should break limitation and field type missing to not inherit from NotFound at all, maybe rather from Missing Implementation.