Deployment SLA Definitions

[dylanbhughes]

This PR adds a new interface to deployments: SLAs. Service Level Agreements (SLAs) describe the intended behavior of the deployment. The first SLA we introduce here is the TimeToCompletionSla, which indicates how long flow runs from the deployment should take. It's possible to configure n SLAs for a given deployment by flow.deploy, prefect deploy ---sla or prefect.yaml. SLAs have different severities, giving users different alerting options for less or more serious violations.

Checklist

• This pull request references any related issue by including "closes <link to issue>"
  • If no issue exists and your change is not a small fix, please create an issue first.
• If this pull request adds new functionality, it includes unit tests that cover the changes
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[codspeed-hq]

CodSpeed Performance Report

Merging #16574 will not alter performance

_{Comparing dylanbhughes/deployment-sla (c1ec262) with main (e004d6a)}

Summary

✅ 3 untouched benchmarks

[zzstoatzz]

we use

from __future__ import annotations

[desertaxle]

Awesome tests! I have a few small comments, but overall this is looking great!

[desertaxle]

LGTM!