Update documentation for the new Environment Timeline

[stevencl840]

Context 🌇

We are replacing the deployment timeline with an environment timeline. This new timeline includes time buckets for grouping deployments, and will be expanded to include information from CI and issue tracking systems. This PR updates the documentation to reflect the move to the environment timeline.

Details 🔍

• Move the documentation to the environment timeline
• Add a redirect on the old environment timeline to the new documentation
• Update the documentation to include being able to access it from the project dashboard and the bucketing of deployments.
• I have not added the version number which switch to the environment timeline, as I could not make it sound natural. Thoughts?

This PR contributed to DEVEX-382

Testing 🧪

You can use the link below to view the new documentation. I was able to link directly to the deployment timeline page and confirm that it attempted to redirect to the environment timeline page. It does this using the production documentation link, so to confirm the link is valid, I edited the URL in the bar to point to the pre-release version

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