The single-values *package* member in a PackageItem was not used,
so remove it -- to show that it really isn't used. This is prep-
work for putting the package name *back*, as multi-valued,
and using the *packages* module.
- point to main Calamares site in the 'part of' headers instead
of to github (this is the "this file is part of Calamares"
opening line for most files).
- remove boilerplate from all source files, CMake modules and completions,
this is the 3-paragraph summary of the GPL-3.0-or-later, which has
a meaning entirely covered by the SPDX tag.
- If there is an item with id "" (empty), it is used as the
"no-package-selected" placeholder text.
- Existing code iterated over the abstract model and used the
name and description at the time the model was set -- but
by getting the name and description from the model, only
a single string was obtained instead of the full range
of translations.
- Therefore, when arriving on the page, the "no-package-selected"
information was displayed from the translation that was active
when the model was set.
Instead, extend the non-abstract model so we can find the no-package-
selected item and pass that explicitly to the page.
FIXES#1241
- These don't have to be static methods of PackageItem, a free
function is more convenient.
- Since it's not API of PackageItem anymore, need to
- update tests not to use API
- do API-not-available warnings in consumers
- Use *appstream* as key in one of the items for the package-
chooser to load data from the AppStream cache in the system.
- Usable for some applications; for DE-selection not so much.
- Currently unimplemented.
- The ID and Screenshot entries might be weird in AppData (in particular,
a remove URL) so put those back under the control of Calamares even
when using AppData as the source of descriptions.
- Doing a manual read of the XML, since existing appdata libraries
don't seem to have a convenient entry for what I need.
- Expand tests to loading AppData (currently, they fail).
