Holidata

- 113 Fix emitter output

- 111 Refactor core classes, replace date parsing and custom date functions with DSL
- 110 Test holidays are only defined for valid regions
- 109 Enable holidata to be calculated outside confirmed range

- Add support for Python 3.12, replace 'snapshottest' with 'syrupy'
- 105 Holiday "Mariä Himmelfahrt" missing for region 'BY' in locale 'de-DE'
(thanks to Alexei Samokvalov)
- Convert DE into module

- 102 Fix error in calculation of 'Day after Thanksgiving'
(thanks to Peter J. Mello)
- 103 Fix region code for Bremen in locale 'DE'
(thanks to Olaf Sebelin)

- Add non-working days for 2024 in country 'HU'
- 97 Merge locale and country
- Fix permalinks for holidays in locale de-DE for region BE

- es-ES: Implement 2024 holidays of Spain
- Drop support for Python 3.7
- Use double quotes instead of single quotes and f-strings