Regularly disable policies linked with no container repositories

🌳 Context

In #330315 (closed), we described a ~performance problem where there were too many cleanup policies enabled for projects with no container images. This made some database indexes used by the background jobs that executes those policies less efficient.

In !61983 (merged), we created a background migration that bulk disable policies in those conditions.

Unfortunately, the background migration missed ~90 000 policies and we created a post deploy migration for those in !63841 (merged).

Now, it's time to disable those policies in a recurrent way. This way, we ensure that database indexes using those policies always reference the optimal set of policies (enabled policies with container repositories)

We have the perfect candidate for that: within the jobs dealing with cleanup policies, we have a cron job that runs each 50min. It can very well, lookup those policies and disable them.

🔍 What does this MR do?

• Update the ContainerExpirationPolicyWorker (cron job) to disable those policies
• Update the related specs
• This process was documented in the breaking changes blog post for %14.0 but this recurrent process is now added to the documentation

📷 Screenshots (strongly suggested)

n / a

📐 Does this MR meet the acceptance criteria?

Conformity

• I have included a changelog entry, or it's not needed. (Does this MR need a changelog?)
• I have added/updated documentation, or it's not needed. (Is documentation required?)
• I have properly separated EE content from FOSS, or this MR is FOSS only. (Where should EE code go?)
• I have added information for database reviewers in the MR description, or it's not needed. (Does this MR have database related changes?)
• I have self-reviewed this MR per code review guidelines.
• This MR does not harm performance, or I have asked a reviewer to help assess the performance impact. (Merge request performance guidelines)
• I have followed the style guides.

Availability and Testing

• [-] I have added/updated tests following the Testing Guide, or it's not needed. (Consider all test levels. See the Test Planning Process.)
• [-] I have tested this MR in all supported browsers, or it's not needed.
• [-] I have informed the Infrastructure department of a default or new setting change per definition of done, or it's not needed.

Security

Does this MR contain changes to processing or storing of credentials or tokens, authorization and authentication methods or other items described in the security review guidelines? If not, then delete this Security section.

• [-] 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

💾 Database Review

So basically, we need to update all expiration policies without any container repository. This update can be slow to be done and so, I used an each_batch loop to limit the number of rows that the query needs to go through.

• min / max of the each_batch loop: !62461 (comment 601980998)
• the actual update: !62461 (comment 601982756)