silx.gui, silx view: Updated default Qt binding to Pyside6; CI: Updated config

[t20100]

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This PR proposes to change the Qt binding priority list to use PySide6 as the default binding.
It also uses PySide6 to generate the Windows executable.

This is worth a major version bump for the next release IMO.

TODO:

• Test Windows application
• Make sure it is OK to use manylinux_2_28

related to #4135, closes #4168

[t20100]

CI seg fault with PySide (see PR #4169 for a fix)

[t20100]

The release workflow is updated to work with PySide6 as the default Qt binding.

Indeed:

• Qt6 requires extra system packages
• PySide6.4 (the minimum required version) requires manylinux_2_28, i.e. Debian 10+, Ubuntu 18.10+.

So with this PR, wheels available on pypi will be manylinux_2_28 instead of manylinux_2014.

It also adds --fail-on-warning when building the documentation to avoid generating the documentation when a module cannot be imported.

[t20100]

In order to avoid copy/paste between CI and release workflows, this PR adds a setup-system composite action.