- 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.
- The configuration for writing the hostname (to /etc/hostname,
to /etc/hosts and possibly to systemd-hostname) is read-only,
because it comes from the config file and won't change after.
- !failed() also means "didn't write the file because it already
exists", which is sometimes acceptable -- but not here.
Use the more-strict bool() conversion, which is only when
the file was actually written.
- Use the createTargetFile() convenience functions to do the
actual work.
- This probably involves more copying around of buffers, since it's
creating one big QString and sending that off, rather than writing
little chunks to a file, but I feel this is worth the code simplification.
- Drops all the error checking for creation, though, because the API for
createTargetFile() lousy.
