Allow arch dependent packages

[AndersBlomdell]

Adds two new options to flatpak-pip-generator:

--arch-dependent-allow Allow arch dependent packages to be used if no arch-independent package can be found. https://github.com/flatpak/flatpak-builder-tools/issues/328 --arch-dependent-force Force arch dependent packages to always be used, Useful if the Sdk doesn't have the tools to rebuild the arch independent package

[bbhtt]

Hi @TingPing, can you please review this? A few latest submissions on Flathub are hitting the issue while trying to use pip-generator for pyside6/shiboken

The only thing I don't like here is the generated manifest is usually copy-pasted without checking. If the flatpak is being built for multiple arches, the build will fail much later. But I don't know how to make that obvious here.