- 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 intended license for the CMake modules is BSD-2-Clause;
there's no desire to restrict what can be done with these,
and CMake modules are generally 2-clause licensed.
CMakeModules/BoostPython3.cmake: Also try e.g. "python37" as the module
name, because Fedora 30 switched from the e.g. "python-py37" format to
that. Otherwise, Boost::Python3 cannot be found on Fedora without
manually setting CALAMARES_BOOST_PYTHON3_COMPONENT.