Refactor `Issuable::Clone::BaseService` to use services

What does this MR do?

This MR refactors Issuable::Clone::BaseService to use services.

Previously Issuable::Clone::BaseService copied an issuable's notes, award emoji, and award emoji on the issuable notes to another issue through Issuable::Clone::ContentRewriter.

As preparatory work for #13426 (closed) we need to be able to copy design notes and their award emoji independently of Issuable::Clone::ContentRewriter which is highly-coupled to issuables.

Issuable::Clone::BaseService now calls three new services:

• Notes::CopyService
• AwardEmoji::CopyService
• MarkdownContentRewriterService

Which contain re-usable logic to perform those actions.

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• [-] Separation of EE specific content

Availability and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers
• [-] Informed Infrastructure department of a default or new setting change, if applicable per definition of done