GraphQL: Deprecate `Projects::ServiceType` interface

What does this MR do and why?

As a part of &6186 (closed), per comment, we are:

• deprecating Project.services
• commenting old objects
• introducing Project.integrations
• introducing new objects
• refactoring existing code

Screenshots

Project.services	Project.integrations

How to set up and validate locally

1. Checkout the current branch
2. Visit graphql-explorer page, http://gdk.test:3000/-/graphql-explorer
3. Look for Project.services, and validate it's deprecated
4. Look for Project.integrations, and validate it's working

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.

Related to #333581 (closed)