EPIC: Tidy Up?

_Re-reading_ the `README.md` of this repo with [***`Shoshin`***](https://en.wikipedia.org/wiki/Shoshin) it feels _cluttered_ and potentially _confusing_. 🤷
Going to spend **`T1h`** doing a tidy up. Don't know when yet. But ideally _soon_. 🔜 👨‍💻

# Todo

+ [x] Move Reference to the "Old" Stack to a new `old-stack.md` file to declutter this one.
+ [x] Finish the Flutter PR: https://github.com/dwyl/technology-stack/pull/80 to close #81
+ [x] Link to `flutter.md` from the `README.md` and explain the context/roadmap.
+ [x] Remove `Redis` and `ElasticSearch` from the Tech Stack diagram.
+ [x] Link to Radical Simplicity https://github.com/nelsonic/nelsonic.github.io/issues/842
+ [x] Update the Tech diagram in the `README.md` https://github.com/dwyl/technology-stack/issues/1#issuecomment-1215832376
+ [x] Close any open [issues](https://github.com/dwyl/technology-stack/issues) that are no longer relevant (backlog grooming).
+ [x] Remove Travis-CI from Continuous Integration Section. 😕
--> See: https://github.com/dwyl/learn-travis/issues/67
+ Create new repo to document our use of GitHub Actions? 💭 `#discuss`