Safety Switch Support

[chengguizi]

For increased safety for arming power output (motors), we should add in support for safety switch and arming light indication, just like standard Pixhawk.

Example product to be integrated:
https://www.aliexpress.com/item/32783506535.html?spm=a2g0o.productlist.0.0.3aeed062ePXA9w&algo_pvid=c65955a9-3bc8-4ddb-8933-21c3093ba7bd&algo_expid=c65955a9-3bc8-4ddb-8933-21c3093ba7bd-30&btsid=0b0a555b16096491259884904e2ac4&ws_ab_test=searchweb0_0,searchweb201602_,searchweb201603_