Make changes to migration and filtering to support default date value

[jloux-brapi]

Description

Story: BI-3066

• Migration modified to support default date value if additional_info.created_date = NULL
• SearchQueryBuilder modified to support filtering ignoring the default date

Dependencies

Testing

• Try filtering Germplasm values on 1970, which is contained in the default value
• Verify unit tests are not failing because they are not supplying created_date

Checklist:

• I have performed a self-review of my own code
• I have tested my code and ensured it meets the acceptance criteria of the story
• I have commented my code, particularly in hard-to-understand areas
• I have either updated the source of truth or arranged for update with product owner if needed https://breedinginsight.atlassian.net/wiki/spaces/BI/pages/1559953409/Source+of+Truth

[humsika]

Code looks good to me.