Draft: Reschedule background migration to backfill `integrations.type_new`

What does this MR do?

This batched background migration failed due to timeouts caused by the automatic batch size optimization.

This adds another post-deployment migration to split up and retry all of the failed jobs.

Follow-up to !66928 (comment 643866372)

Issue: #333507 (closed), part of the epic &2504 (closed) to rename "services" to "integrations", and specifically the child epic &6177 (closed).

Migration output

$ rails db:migrate:up VERSION=20210805120749
== 20210805120749 RescheduleBackfillIntegrationsTypeNew: migrating ============
== 20210805120749 RescheduleBackfillIntegrationsTypeNew: migrated (0.0480s) ===

$ rails db:migrate:down VERSION=20210805120749
== 20210805120749 RescheduleBackfillIntegrationsTypeNew: reverting ============
== 20210805120749 RescheduleBackfillIntegrationsTypeNew: reverted (0.0000s) ===

Does this MR meet the acceptance criteria?

Conformity

• I have included changelog trailers, or none are 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.
• This change is backwards compatible across updates, or this does not apply.

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.

Related to #333507 (closed)