Release notes for 0.100.0 (#1617)

* Release notes for `0.100.0`

Please add your new features and breaking changes to the release notes
by opening PRs against the `release-notes-0.100.0` branch.

## TODO
- [ ] look at interesting contributions
- [ ] write all the sections
- [ ] order the sections by interest
- [ ] add the breaking changes
- [ ] detail the breaking changes
- [ ] add the full changelog
- [ ] complete all the `TODO`s inside the release note
- [ ] ... (PRs that need to land before the release, e.g. [deprecations](https://github.com/nushell/nushell/labels/deprecation) or [removals](https://github.com/nushell/nushell/pulls?q=is%3Apr+is%3Aopen+label%3Aremoval-after-deprecation))

* Start 0.100.0 release notes (#1626)

* add plugin list change

* footer inheritance and congrats

* some more PRs

* Release notes changes for 0.100.0 (#1627)

* Continue release notes

* Finish PRs and changes

* Update release note (#1628)

* some cleanup + mention AST eval removal next release

* remaining PRs

* do some cleanup, reordering

* finish everything else :p

* ah - clean up + note about release schedule

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Co-authored-by: Devyn Cairns <[email protected]>
Co-authored-by: Justin Ma <[email protected]>

Author: 3 people