Change procedure data fields to required (list provided)

Change following fields to required, according to spec table: https://confluence-sale.prozorro.org/pages/viewpage.action?pageId=50364622

• 1. data.value
• 2. data.description
• 3. data.lotIdentifier
• 4. data.procuringEntity.identifier.legalName
• 5. data.procuringEntity.identifier.uri
• 6. data.procuringEntity.identifier.scheme
• 7. data.procuringEntity.address.countryName
• 8. data.procuringEntity.address.region
• 9. data.procuringEntity.address.locality
• 10. data.procuringEntity.address.streetAddress
• 11. data.procuringEntity.address.postalCode
• 12. data.minimal_step
• 13. data.guarantee
• 14. data.items