Make auto refresh interval configurable

[rachelwigell]

closes: #18069

We accidentally DDOS'd our own webserver yesterday 😄 More details in the issue on how exactly this happened, but the gist is that auto-refresh can be a significant strain if there are many active tasks whose statuses must be polled. Auto-refresh is a wonderful feature but we wanted to be able to lengthen the interval to protect against this.

On main, the interval is hard-coded to 3 seconds. I'm proposing we add a new webserver config variable that will allow this interval to be customized.

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[boring-cyborg]

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[msumit]

This is nice 👍. Along with this, I think it would be good to have an option (like a drop-down) near the auto-refresh control to set the refresh rate by the users themselves, which will be stored into browser's local storage or a cookie and can control a user's choice to refresh the data.

[github-actions]

The PR most likely needs to run full matrix of tests because it modifies parts of the core of Airflow. However, committers might decide to merge it quickly and take the risk. If they don't merge it quickly - please rebase it to the latest main at your convenience, or amend the last commit of the PR, and push it with --force-with-lease.

[rachelwigell]

Along with this, I think it would be good to have an option (like a drop-down) near the auto-refresh control to set the refresh rate by the users themselves, which will be stored into browser's local storage or a cookie and can control a user's choice to refresh the data.

I agree that would be a convenient feature, but undermines the original intent of making this change which was to allow admins of an Airflow server to set a longer interval for auto-refresh so that users wouldn't be as easily able to overwhelm the webserver with large numbers of requests.

[boring-cyborg]

Awesome work, congrats on your first merged pull request!