tests: test against multiple Qiskit versions

[airwoodix]

Summary

Improve the testing coverage:

• test examples against the installed packages instead of the source checkout
• test against multiple (hand-selected) versions of Qiskit.

Since the package is still compatible with Qiskit 0.46, lower the bound accordingly (was raised in #141).

Details and comments

The build system is migrated from Poetry to Hatch / Hatchlings and the dependency resolution on CI to uv. The latter provides dependency resolution overrides, which are used for the dependency matrix testing. However, it is still quite experimental, thus the number of workarounds.

Windows tests (examples on the built package only, as previously) shall be re-enabled later, as they require a platform-agnostic runner for the examples.

[wilfried-huss]

Hatch has now native support for UV.

Maybe this can help to simplify this pull request.