Create a Keybase docker file and migrate bot-sshca to the shared parent image

[ddworken]

Currentlly Dockerfile-ca and Dockerfile-kssh are nearly the same file since both involve installing and setting up Keybase inside of Docker. In the future once we have an official Keybase docker image, migrate this repository to reference it.

[Johannestegner]

I created a Ubuntu (bionic) based Keybase image which you can copy if you wish (totally okay to use the image directly too if you want, but it is using one of my base images)!

https://gitlab.com/jitesoft/dockerfiles/keybase/blob/master/Dockerfile
https://github.com/jitesoft/docker-keybase/blob/master/Dockerfile

Haven't yet figured out how to build it from source, else it would have been alpine based... ;P

[ddworken]

Thanks for the links! I think ultimately the plan is to create an official keybase docker image that follows our release cycle (and is built by us) so that it becomes easier to run Keybase inside of docker in the future. So I think for now, I'll stick with our current Dockerfiles (though I do like your gpg signature verification, so I'll probably add that :)).

[Johannestegner]

Hehe, all good and understandable :)