Add Managed Identity ACI Prefect Worker recipe

[prefectcboyd]

Description

What's cooking?

This recipe adds files, configuration, and README for provisioning a Prefect ACI Worker and Managed Identity.
Steps are provided for each component - it is intended to be used for a private repository, where identity is used to retrieve credentials from a KeyVault instead of secrets within Prefect.
It can be used without identity, solely as an instructional setup for ACI.

New Recipe Checklist

• My PR is in the format of Add <project-name> recipe
• My recipe is reproducible and explains everything needed to run successfully. If my code has external dependencies, I make mention of them.
• My code is easily understandable and/or well-commented.
• If my recipe requires a new category (e.g. creating a monitoring/ folder in devops/), I have encapsulated my project within its own subfolder so that others can add their own recipes as well.
• If my recipe uses Prefect < 2.0, my code is within the prefect-v1-legacy/ folder.

[github-advanced-security]

CodeQL found more than 10 potential problems in the proposed changes. Check the Files changed tab for more details.

[serinamarie]

Moving this to draft until @prefectcboyd finds a reviewer.

[serinamarie]

Closing but feel free to reopen anytime @prefectcboyd