Implement AzureResultHandler

[frsann]

Thanks for contributing to Prefect!

Please describe your work and make sure your PR:

• adds new tests (if appropriate)
• updates CHANGELOG.md (if appropriate)
• updates docstrings for any new functions or function arguments, including docs/outline.toml for API reference docs (if appropriate)

Note that your PR will not be reviewed unless all three boxes are checked.

What does this PR change?

Adds AzureResultHandler for for handling results to / from Azure Blob storage containers.

Why is this PR important?

It helps users on the Azure platform to handle results.

[marvin-robot]

Here I am, brain the size of a planet and they ask me to welcome you to Prefect.

So, welcome to the community @frsann! 🎉 🎉

[codecov]

Codecov Report

Merging #1421 into master will decrease coverage by 0.17%.
The diff coverage is 76.56%.

[cicdw]

Wow @frsann - I'm impressed! This is a clean implementation of a new result handler, and you covered all the standard issues. Very well done and thank you for the contribution!