Release notes for 0.2.0-testing.1

[ghislaineguerin]

Release notes for 0.2.0-testing.1

---

Update by Kriti

I basically rewrote the release notes, added screenshots and some write ups, re-ran the release notes script and added missing PRs, recategorized many PRs,. added the notes to the nav, and made some other improvements.

I also added a note to the docs homepage about the testing build and feedback.

[kgodey]

@ghislaineguerin the list of required reviewers is tracked in Asana, please check that in the future – I added myself and Brent this time. I also added the PR status label, please also check that in the future.

[kgodey]

Thanks @pavish and @mathemancer for the changes, they look good. I made a minor docs change and also responded to @pavish's comments.

Unassigning myself, leaving assigned to @seancolsen since he's the sole remaining reviewer.