Draft: Split .rubocop_manual_todo.yml into file per cop

What does this MR do?

This avoids heavy churn on a single file .rubocop_manual_todo.yml and paves the way for .rubocop_todo.yml to be split up similarity to remove the difference between manual and automatic todos.

Leaving .rubocop_manual_todo.yml for now for documentation purposes.

TODO

• Adjust development guidelines

Verification

bundle exec rubocop --show-cops shows not differences before and after the change.

	Before	After
REVEAL_RUBOCOP_TODO=0	before	after
REVEAL_RUBOCOP_TODO=1	before.reveal	after.reveal

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

Security

If this MR contains changes to processing or storing of credentials or tokens, authorization and authentication methods and other items described in the security review guidelines:

• Label as security and @ mention @gitlab-com/gl-security/appsec
• The MR includes necessary changes to maintain consistency between UI, API, email, or other methods
• Security reports checked/validated by a reviewer from the AppSec team