pre-commit hook

[svx]

Currently when we do a git push, docker hub is triggered and building a new container, so far so good.

I would like to improve that:

• test documentation before each build
• run docker lint

With that in place we would make sure, that we always have docs without typos or broken links, our dockerfiles following best practices about a dockerfile should be written.

Since we are talking docker, this would be really easy doable with a container, there is already a container, which the docs team uses, we could easily adjust that one or use it as a basis for an own one.

With that we would get the following pipeline:

work on ct/ct-docs -> git commit -> running tests -> if OK push to dockerhub, else fix and test again