Make Import/Export more resilient to errors
We should ignore all model validations importing GitLab Projects using the Import/Export. We can still error out but continue with the import process. This will prevent many of the current issues to do with DB inconsistency or complex validators.
Also, we should revisit the places where we just log an error and mark the import as failed to see if we can ignore and continue with those errors.
Other objectives:
- Improve import retrying behavior.
- Improve the performance
- Improved error messages (see https://gitlab.com/gitlab-org/gitlab-ce/issues/40640)
This will prevent future issues like this validation error
Edited by Jeremy Watson (ex-GitLab)