10/docs/migration path for existing users (#11)

* Document migration path

* Document release process

* Restructure changelog

* Update docs/getting-started/migration.rst

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* Update README.md

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Fix copliot stylistic warnings

* Update docs/getting-started/migration.rst

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>

* Update docs/getting-started/migration.rst

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* Update docs/getting-started/migration.rst

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* Update docs/maintainers/versioning-and-releases.rst

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* README: Copilot suggestions

* README: Inlcude Django/DRF upgrade in migration short notice

* Update README.md

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* Update docs/getting-started/migration.rst

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Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>