[Docs] Document FlyteAdmin DB migration best practices

[katrogan]

Description

Somewhere within the contributors guide we should call out that since FlyteAdmin is backed by RBDMS special considerations must be given to model migrations. Specifically that:

• they should always be additive
• they should never alter existing column types

Furthermore we should have upgrade best practices to document blue/green deploys to help users avoid downtime for potentially expensive migrations when upgrading flyte admin releases

Are you sure this issue hasn't been raised already?

• [X] Yes

Have you read the Code of Conduct?

• [X] Yes

[github-actions[bot]]

Hello 👋, This issue has been inactive for over 9 months. To help maintain a clean and focused backlog, we'll be marking this issue as stale and will close the issue if we detect no activity in the next 7 days. Thank you for your contribution and understanding! 🙏

[github-actions[bot]]

Hello 👋, This issue has been inactive for over 9 months and hasn't received any updates since it was marked as stale. We'll be closing this issue for now, but if you believe this issue is still relevant, please feel free to reopen it. Thank you for your contribution and understanding! 🙏

[github-actions[bot]]

Hello 👋, this issue has been inactive for over 9 months. To help maintain a clean and focused backlog, we'll be marking this issue as stale and will engage on it to decide if it is still applicable. Thank you for your contribution and understanding! 🙏