Move build system to CMake

[dacav]

Is your feature request related to a problem?

Autoconf feels difficult to work with.

Describe the solution that you'd like

Switch to a more modern build system.

CMake is a good choice. Other projects in the same stack (e.g. libfido2) already use it.

Describe the alternatives that you've considered

Plenty of competing build systems are available.

In practice, on modern systems it might be even possible to just use plain Makefiles, and using pkgconfig for dependency checking