Follow-up from "Add ClickHouse structure SQL and rake tasks"

The following discussion from !192771 (closed) should be addressed:

• @pshutsin started a discussion: (+1 comment)

  neat-pick: we have this click_house_database_names.each do |database| many times in this file. Maybe it's better to restructure it differently:

  click_house_database_names.each do |database|
    namespace :reset do
      task database => :environment do
        # ...
      end
    end
    
    namespace :migrate do
      task database => :environment do
        # ...
      end
    end
  
    namespace :schema do
      namespace :load do
        task database => :environment do
          # ...
        end      
      end
    end
  end