This reverts commit 2fb58dc01c.
The original commit included an unexpected deletion of _all_
translations in certain languages. This was unintented, and appears to
have been a merging artefact.
This change will be re-submitted as a separate PR.
A long period of hand-editing caused these to fall out of sync with
what would have been generated from the source.
These were regnerated using the qt5_create_translation macro in the
root CMakeLists, and then using lconvert to merge the completely blank
translation files with the existing translations.
Rather than a drop down dialog, which could present users with images
that may not run on their hardware, allow selection of Raspberry Pi as a
first stage. If users adopt this feature, they are presented with a
subset of images that we know will actually run on their hardware.
This is achieved by leveraging @maxnet's excellent OS filtering scheme.
Future work will attach image and description support to this OS list.
