Add support for Flask-SQLAlchemy-Lite datastore

[jwag956]

• This introduces new pre-configured models that use 'modern' sqlalchemy type annotations
• The querying is done using the 2.0 select() mechanism (rather than the old query interface)
• Enhance view_scaffold test harness to work with either Flask-SQLAlchemy or Flask-SQLAlchemy-Lite
• FS-Lite requires newer Flask/Werkzeug - bump up lowest tested versions
• per sqlalchemy best practice - don't install mypy extension or stubs

close #989

[codecov[bot]]

Codecov Report

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

Project coverage is 98.49%. Comparing base (ec70c1d) to head (5f07f1c).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## master #994 +/- ## ========================================== + Coverage 98.45% 98.49% +0.03% ========================================== Files 36 37 +1 Lines 4665 4777 +112 ========================================== + Hits 4593 4705 +112 Misses 72 72 ```

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