chore: remove Milestone module and update related schemas

- Deleted the MilestoneModule and its associated schema to streamline the codebase.
- Updated QuizSchema to replace scheduleId with serviceId, enhancing the relationship structure.
- Removed references to Milestone in ServiceSchema, improving clarity and focus on relevant entities.
- Updated Prisma types to reflect the removal of Milestone, ensuring data integrity across the application.

src/Service/service.schema.ts

@@ -102,9 +102,6 @@ export class ServiceSchema extends PothosSchema {
         workshop: t.relation('workshop', {
           description: 'The workshop for the service.',
         }),
-        milestone: t.relation('milestone', {
-          description: 'The milestone for the service.',
-        }),
         serviceAndCategory: t.relation('serviceAndCategory', {
           description: 'The service and category for the service.',
         }),