[Backend] Add the ability to manage a default project compliance framework on groups

Problem description

This issue is an iteration in developing Group-level setting for default compliance fram... (&8815 - closed).

Proposal

Add the ability to CRUD a default compliance framework on namespaces.

Implementation plan

backend 3️⃣

1. Update ee/app/services/ee/projects/create_service.rb so that whenever a new project is under a group and the group has set a default compliance framework then create a new ComplianceManagement::ComplianceFramework::ProjectSettings with project_id as the current project and framework_id = project.root_namespace.default_compliance_framework.id). We can define a method default_compliance_framework in group.rb as follows:

def default_compliance_framework
  default_compliance_framework_id = namespace_settings.default_compliance_framework
  ComplianceManagement::Framework.where(id: default_compliance_framework_id)
end

2. Whenever a framework is deleted check if it is the default framework, in case it is then prevent the deletion and show an error message to the user.
3. Add a default field to the Types::ComplianceManagement::ComplianceFrameworkType, something like the diff below:

diff --git a/ee/app/graphql/types/compliance_management/compliance_framework_type.rb b/ee/app/graphql/types/compliance_management/compliance_framework_type.rb
index 7f80b916c0c0..1f4c1102ba86 100644
--- a/ee/app/graphql/types/compliance_management/compliance_framework_type.rb
+++ b/ee/app/graphql/types/compliance_management/compliance_framework_type.rb
@@ -27,6 +27,13 @@ class ComplianceFrameworkType < Types::BaseObject
             null: true,
             description: 'Full path of the compliance pipeline configuration stored in a project repository, such as `.gitlab/.compliance-gitlab-ci.yml@compliance/hipaa` **(ULTIMATE)**.',
             authorize: :manage_group_level_compliance_pipeline_config
+
+      field :default, GraphQL::Types::Boolean,
+            null: false, description: 'Default compliance framework for the group.'
+
+      def default
+        object.id == object.namespace.namespace_settings.default_compliance_framework
+      end
     end
   end
 end

4. Update the Types::ComplianceManagement::ComplianceFrameworkInputType to also accept an optional boolean argument default, this will be used by frontend to set and remove default compliance frameworks.