MVP version of post-import utilities for teams who have migrated from Pivotal to Shortcut

[tomngo]

See pivotal-import/post-import-utilities/README.md.

[semperos]

This is a sizable contribution, and exciting to see you extend so thoroughly what the importer offers by default.

Wanted to comment here to let you know I've seen this submission and will be reviewing it this week. Thank you!

[semperos]

Given the value of this contribution, after having reviewed it for security-related concerns and found nothing problematic in that regard, I'm going to approve and merge this pull request.

The ShortcutObject appears to write exclusively on a one-by-one basis. To improve performance especially for large numbers of edits, the Update Multiple Stories endpoint could be leveraged for stories (no such endpoint for epics, unfortunately) by batching the operations, an example of which can be found in the main importer code.

Thank you for also documenting this addition in its own README. The code formatting is highly legible, if different from the code formatter used for the primary import code, and given there is a certain timeline wherein the importer and your additions will prove most useful to others, having complete code style uniformity is not a top priority.

@tomngo I and the Shortcut team are grateful for your code contributions here and your collaboration in our Slack community!

[semperos]

I've left a separate standalone comment explaining my review.