Initial support to automate release flow. Now after git tag of specific commit GitHub Actions will create a draft entry of release (named by tag) with source code package on it.
This type of console is enabled only with `-svgalib` and `-dedicated` options. Since there no svgalib direct support (which is pretty old and too specific to Linux tech), it's better completely remove this code for simplicity and reducing external dependencies.
Removed `-svgalib` option as unused now.
Added installation steps for all built targets. Added FORCE_PORTABLE_INSTALL cmake option that controls portable installation (only supported for now).
Before this change, the CI script had a special step that would ensure
that CI artifacts contained a copy of Descent 3’s license. This change
replaces that special CI step with a CMake target.
The main motivation behind this change is to make it easier for people
to create packages for Descent 3. Before this change, if you wanted to
create a package for Descent 3, then you would have to manually ensure
that your package contained a copy of the GPL.
The GPL requires that you include a copy of the GPL with every copy of
programs that are released under the GPL [1]. Before this change, CI
artifacts didn’t include a copy of the GPL.
Fixes#276.
[1]: <https://www.gnu.org/licenses/gpl-faq.en.html#WhyMustIInclude>
Currently Windows gets this from vcpkg. Mac will get it from Homebrew,
and the GitHub linux builders will just install it with apt-get.
This might not be the perfect solution (having to install Homebrew is a pain,
GitHub Actions has an ancient SDL2), but it gets all the common platforms
running for now without much fuss.
