Added scripts for Foxconn SDX55, Quectel EM120, and several old Sierra
Wireless manufactured devices:
* Installed but not used by default, the user needs to setup manual
links from ${pkgdatadir}/fcc-unlock.available.d, to
${pkgsysconfdir}/fcc-unlock.d in order to enable them.
* Installed with rights only for the owner, so that the dispatcher in
ModemManager can validate them.
* They rely on $PATH to find the qmicli/mbimcli tools.
In addition to these scripts, per-vid:pid links are created in the
same ${pkgdatadir}/fcc-unlock.available.d directory, specifying which
are the specific devices that require the FCC unlock operation.
This patch also creates the ${pkgsysconfdir}/fcc-unlock.d and
${pkglibdir}/fcc-unlock.d directories where ModemManager looks for the
enabled tools.
Note that the meson setup doesn't support creating/deleting links
officially yet, so we use a workaround using meson.add_install_script
that is not perfect (i.e. doesn't handle the symlink removal during
uninstall). See https://github.com/mesonbuild/meson/issues/1602
e7a6bb7504
