Add ZTE Kis3 / ZTE Open C

Hello! 👋 This PR adds support for the ZTE Open C, a slightly different version of the ZTE Kis 3* that runs Firefox OS. (That is if it wasn't a defunct project :roll_eyes: ) Currently there's no display output, but it does boot to a shell over ssh (very slow boot, be patient!) *I stuck with the ZTE Kis 3 name as most of the preivous work by @KonstaT uses the same naming conventions.