Introduce FreeBSD CI

Plugins and their tests are not ran yet, TBD later

Make compatible with CMake 4

Make static runtime default and build with native ARM runners

Switch to Docker --platform

Improve logging of failed subprocesses

Set up ARM builds with QEMU and Docker

This commit allows us to provide both 32-bit and 64-bit ARM binaries for our users.

Checking if a path is a directory is broken

Checking if a path is a directory, by checking if there is a slash
at the end of the path, was inconsistent and broken in one case.
All string checks of paths being a directory are now the same.

Log start of plugin probing

Occasionally, linuxdeploy becomes unresponsive during plugin detection because a plugin is hanging. In those cases, we need to know which one causes the problem.

Use Ubuntu focal to be able to build i386 AppImages

Use Ubuntu focal to be able to build i386 AppImages