- 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
Package chooser is a **low density** package selector -- unlike
netinstall which offers a high density tree view -- for picking
zero, one, or more items from a small collection of packages.
This can be used, e.g., for "pick exactly one desktop environment",
"pick zero or more text editors" which can then be installed
by another module. The UI is big and shiny (rather than netinstall's
text-based tree view) and isn't suitable for more than a dozen or
so items.
