Allow JCMA to migrate deltas when a project migration fails

Ideally, JCMA should allow for deltas to be migrated if a project fails during a migration plan. This will allow admins to re-run a migration without having to delete the project in Cloud and save time by only migrating the elements that failed.

The current proposed run book for failed projects is to delete in Cloud and remigrate, but this can pose some challenges if we're working with a large projects because:

1) Project deletions are long running tasks in Cloud and it can take hours to delete a project

2) Migration deadlines can be affected by having to remigrate X% of projects

Suggested Solution

Allow for a retry mechanism that would only migrate deltas (missing items that failed on the first run). This will allow migrations to benefit from a faster migration in the case a project fails.