Swift 6.0 todo

# Swift 6.0

This will likely be one of the largest updates to the track to this date.
To make the track more future proof and inline with the direction the language is going, will we switch from XCTest to Swift-Testing.
This is a huge undertaking which involves rewriting 100+ test files, this will also require a brand new test runner.

## Docs

- [ ] README (#821)
- [ ] Test Doc (#826)
- [ ] Learning Doc (#839
- [ ] Installation Doc (#840)

## Tooling

- [ ] New Test runner (https://github.com/exercism/swift-test-runner/pull/58)
- [ ] Introduce Analyzer (https://github.com/exercism/swift-analyzer/pull/3)
- [x] Updated Test Generator (#782)
- [x] Update ci to Swift 6.0 (#806)
- [x] Fix numerics dependency (#842)
- [ ] Linux ci, checking multiple versions, pined Swift version (#841)

## New concept / New Concept exercises

- [ ] Ranges / ChessBoard (#823)
- [ ] For Loops / Bird Watcher (#824)

## Concept

- [ ] #807
- [ ] #817
- [ ] #827
- [ ] #828
- [ ] #829
- [ ] #830
- [ ] #831
- [ ] #832
- [ ] #833
- [ ] #836
- [ ] #838
- [ ] #844

## Exercises

- [ ] Armstrong Numbers, ~~update to include int128 tests~~ (postponed due to missing pow function) (#784)
- [ ] #785
- [ ] #786
- [ ] #787
- [ ] #788
- [ ] #789
- [ ] #790
- [ ] #791
- [ ] #792
- [ ] #793
- [ ] #794
- [ ] #795
- [ ] #796
- [ ] #797
- [ ] #798
- [ ] #799
- [ ] #800
- [ ] #801
- [ ] #802
- [ ] #803
- [ ] #804
- [ ] #808
- [ ] #816
- [ ] #822
- [ ] Deprecate exercises based on problem spec, only scale generator will remain compatible with Swift 6.0 of the deprecated exercises (#805)

Update all test file to Swift testing