Introduce Admin users

[zaychenko-sergei]

• Core:
  • Extend AccountInfo structure with a boolean property (isAdmin)
  • Extend CurrentAccountSubject with a similar boolean property
• OSO Authorizer:
  • Modeling admin property in user structure
  • Admin users should be able to read or write any dataset regardless of ownership, privacy details.
• HTTP:
  • Support admin flag propagation in AuthenticationMiddleware
• GraphQL:
  • Extend GraphQL API equivalent of AccountInfo structure
  • Introduce AdminGuard for GraphQL queries allowed only for admins
  • Create an API sketch for admin-specific functionality without implementation - just to check the guard works fine:
  • list all tasks in the system regardless of the dataset (new API)
• CLI:
  • UsersConfig structure should hold optional isAdmin marker, false by default. It should define the built-in account’s data.
  • Support flag propagation in AccountService.
• OAuth:
  • No GitHub-driven admins model at this stage. All users stay with current privileges.