feat: Add system disclosed attributes for contact phone numbers

[OlegPhenomenon]

• Add system_disclosed_attributes array column to contacts table
• Update OrgRegistrantPhoneCheckerJob to manage both user and system disclosed attributes
• Include system_disclosed_attributes in contact API serializer

This change introduces a new way to track system-level disclosure of contact attributes, separate from user-defined disclosures. When a phone number matches the company register data, it will be marked as disclosed both in user and system attributes. This allows better tracking of which attributes were automatically disclosed by the system versus manually disclosed by users.

[mmeest]

I've tested the solution for displaying phone number in rest-whois.

Test Environment:

• Both registry and rest-whois running in test environment
• Tested with Company Register test data

Test Scenarios:

1. Estonian organization with matching phone number (from Company Register)
2. Estonian organization with non-matching phone number
3. Estonian private person
4. Foreign organization
5. Foreign private person

Results:
The solution works as expected: phone number is displayed in rest-whois only when:

• The registrant is an Estonian organization (ident_type: 'org', ident_country_code: 'EE')
• AND the phone number matches the number published in Estonian Business Registry

In all other cases, the phone number shows "Not Disclosed" as expected.