Create images for Cylc 8

[kinow]

Similarly to how we package everything in conda, we should be able to package everything necessary with docker.

We may need a couple of images for cylc-flow, cylc-uiserver + jupyterhub + cylc-ui. Possibly just one container type for each (e.g. cylc-flow-alpine, cylc-alpine, etc, no need to build debian/ubuntu/etc).

[sadielbartholomew]

Sorry, I know you have picked it out as a good candidate for Hacktoberfest, but for some personal learning this one would be great for me to do, so I'd quite like to tackle this Issue if that's okay?

[kinow]

Hi @sadielbartholomew !

Sure! Sorry, I went on a frenzy adding that label without thinking too much 😬 I remember now you said you wanted to work on this one. Label removed! And feel free to ping me if you need any help.