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.
Something like `MissingImplementation` extending `RuntimeException` seems ok to me. We have `NotImplementedException` but this is for when implementation is missing intentionally. Skype? :)