This creates an alpine-meson binary that is a shellscript that carries the default values we think are best for packaging stuff in Alpine Linux, they can of course be overridden in the APKBUILD by passing the same options at the end.
It uses the same concept as the arch-meson from Arch Linux, the extra values are taken from https://mesonbuild.com/Builtin-options.html and from some peeking at Void Linux's meson build-style.
This should allow us to make sweeping changes to APKBUILDs with a single change in a knob instead of on every template, such as the recent changes to --buildtype=plain and CMake's -DCMAKE_BUILD_TYPE=None.
auto-features should be disabled but that would lead some packages like gstreamer requiring the APKBUILD writer to switch up more than 60 lines.