Create GraphQL Query for Pages Settings

In order to move the pages UI to vue we need to expose Pages Settings with GraphQL. We should add the following fields to the Project type.

type Project {
  pagesForceHttps: Boolean
  pagesUseUniqueDomain: Boolean
}

Implementation Guide

The mentioned attributes already exist in rails' Project class, so all that needs to be done is adding them as a field to app/graphql/types/project_type.rb.

The field should also be added to the spec in line 18 ff. in spec/graphql/types/project_type_spec.rb.

For testing GraphQL queries we primarily rely on Integration Tests, see our documentation on writing specs for GraphQL here: https://docs.gitlab.com/ee/development/api_graphql_styleguide.html#testing