[Replicant] [replicant 6] Add shutdown and reboot scripts

[Denis 'GNUtoo' Carikli]

These scripts can be used to cleanly shutdown and reboot the device,
similar to when users use the power menu.

In addition to the patch that will follow in a response to
this mail, here's an URL to the see the vendor_replicant patch in a web interface:
https://git.replicant.us/contrib/GNUtoo/vendor_replicant/commit/?id=59246bbb10ecd21c66b69f78e3a095912f17a47d

And here's how to get it in a git repository:
git clone https://git.replicant.us/GNUtoo/vendor_replicant
cd vendor_replicant
git show 59246bbb10ecd21c66b69f78e3a095912f17a47d

And for the vendor_replicant-scripts patch:
https://git.replicant.us/contrib/GNUtoo/vendor_replicant-scripts/commit/?id=4a29cc58608439ffe96c869145f4f0c97971826c

And here's how to get it in a git repository:
git clone https://git.replicant.us/GNUtoo/vendor_replicant-scripts
cd vendor_replicant-scripts
git show 4a29cc58608439ffe96c869145f4f0c97971826c

Denis.