For some reason, the ModemManager build tends to freeze when built
with QEMU user emulation for arm*. Changing the build to use a single
thread only (-j1) avoids that, although the build is slower of course.
The same thing seems to happen fo oFono as well, so set that to -j1 too.
Also limit building to "armhf armv7 aarch64" since the forks are not
needed on any other architectures, to reduce build times a bit. The
other architectures can just use the upstream packages from Alpine.
Default dbus policy of ofono allows only root user and users who are
logged into tty using at_console policy. However since our dbus is not
built with elogind, at_console is never set.
This allows user in wheel group to access ofono
[ci:skip-build]: already built successfully in CI
