Adapt project to current 1.23 iter API

[BooleanCat]

Please provide a brief description of the change.

• All iterators now natively return and use the Seq types rather than this projects type alias, favouring compatibility with the standard library over convenience features like chaining.
• Added iterators for the Seq2 variants of existing iterators
• Renamed Lift to Values and moved to future shadow package slices (to be deleted when Go 1.23 is released)
• Renamed LiftHashMap to All and moved to future shadow package maps (to be deleted when Go 1.23 is released)

Which issue does this change relate to?

None.

Contribution checklist.

• [x] I have read and understood the CONTRIBUTING guidelines
• [x] My code is formatted (make check)
• [x] I have run tests (make test)
• [x] All commits in my PR conform to the commit hygiene section
• [x] I have added relevant tests
• [x] I have not added any dependencies

Additional context

There are breaking changes here.

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 100.00%. Comparing base (0dff3ac) to head (0348804).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## v2 #106 +/- ## ========================================= Coverage 100.00% 100.00% ========================================= Files 11 13 +2 Lines 232 271 +39 ========================================= + Hits 232 271 +39 ```

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