Start using new table for instance integrations (using feature flag)

Everyone can contribute. Help move this issue forward while earning points, leveling up and collecting rewards.

As part of &14638 at this point we should have identical amount of records of instance integrations in integrations table and mirroring records in instance_integrations tables, which should be ready to perform a swap of using integrations to instance_integrations.

Proposed solution

  1. Update existing usages of instance integrations that use integrations records to use instance_integrations
  2. Add a feature flag to swap to the new table records
Edited by 🤖 GitLab Bot 🤖