Rake task for registry and whois apps to synchonize database structure with rest-whois

[artur-intech]

Use https://github.com/internetee/rest-whois/blob/master/db/schema.rb as a single source of truth (structure.sql if schema.rb does not work).

Remove:

• https://github.com/internetee/registry/blob/master/db/whois_schema.rb
• https://github.com/internetee/whois/blob/master/db/schema.rb