Add ARM version of container

[smiffy6969]

Need to do this for my pi 2, tweaking the dockerfile FROM: to base on a ubuntu ARM, works great.....

thanks

Paul

[demaniak]

@smiffy6969 - you don't maybe wanna throw in a PR there?

[demaniak]

@smiffy6969 you can try out https://hub.docker.com/r/demaniak/armhf-noip/ , see if that works for you.

[jorkzijlstra]

Any plans for an ARM64 based image?