Place classes under EpicBoards

- EpicBoards is less confusing than Epics

ee/app/graphql/ee/types/mutation_type.rb

@@ -36,7 +36,7 @@ module EE
         mount_mutation ::Mutations::Vulnerabilities::DestroyExternalIssueLink
         mount_mutation ::Mutations::Boards::Update
         mount_mutation ::Mutations::Boards::UpdateEpicUserPreferences
-        mount_mutation ::Mutations::Boards::Epics::Create
+        mount_mutation ::Mutations::Boards::EpicBoards::Create
         mount_mutation ::Mutations::Boards::Lists::UpdateLimitMetrics
         mount_mutation ::Mutations::InstanceSecurityDashboard::AddProject
         mount_mutation ::Mutations::InstanceSecurityDashboard::RemoveProject

ee/app/graphql/mutations/boards/epics/create.rb → ee/app/graphql/mutations/boards/epic_boards/create.rb

@@ -2,7 +2,7 @@
 
 module Mutations
   module Boards
-    module Epics
+    module EpicBoards
       class Create < ::Mutations::BaseMutation
         include Mutations::ResolvesGroup
         include Mutations::Boards::CommonMutationArguments
@@ -20,7 +20,7 @@ module Mutations
           group_path = args.delete(:group_path)
 
           group = authorized_find!(group_path: group_path)
-          service_response = ::Boards::Epics::CreateService.new(group, current_user, args).execute
+          service_response = ::Boards::EpicBoards::CreateService.new(group, current_user, args).execute
 
           {
             epic_board: service_response.payload,

ee/app/services/boards/epics/create_service.rb → ee/app/services/boards/epic_boards/create_service.rb

 # frozen_string_literal: true
 
 module Boards
-  module Epics
+  module EpicBoards
     class CreateService < Boards::CreateService
       extend ::Gitlab::Utils::Override
 

ee/spec/graphql/mutations/boards/epics/create_spec.rb → ee/spec/graphql/mutations/boards/epic_boards/create_spec.rb

@@ -2,7 +2,7 @@
 
 require 'spec_helper'
 
-RSpec.describe Mutations::Boards::Epics::Create do
+RSpec.describe ::Mutations::Boards::EpicBoards::Create do
   include GraphqlHelpers
 
   let_it_be(:current_user) { create(:user) }

ee/spec/services/boards/epics/create_service_spec.rb → ee/spec/services/boards/epic_boards/create_service_spec.rb

@@ -2,7 +2,7 @@
 
 require 'spec_helper'
 
-RSpec.describe Boards::Epics::CreateService, services: true do
+RSpec.describe Boards::EpicBoards::CreateService, services: true do
   def created_board
     service.execute.payload
   end