Adding container setup

[4c0n]

For development it would be very nice to have a Dockerfile to be able to build some containers for Sylius with the theme installed.
That way we have an integrated toolchain and all the other advantages of running in containers.

My suggestion is to re-use the setup from Sylius-Standard for a big part and pre-install the theme.

[pocky]

Big 👍 for this.
This dockerfile should be in SkeletonPlugin and Sylius-Standard too 😄

[4c0n]

No worries I can take care of this. Just need a little time :)

[anthid]

I can help too. But I think we need some changes in Behat code to be able to run tests against Bootstrap theme, isn't it?

[4c0n]

@anthid It should be a separate issue, but you currently are right about that. I opened this issue: Sylius/Sylius#11622

There is also an example included of the way I currently work around that for plugins. I feel pretty confident that we can make it work, maybe it won't be as big of an issue in this case as we just want to run the tests against the theme, not against the standard ui and the theme. If some selectors aren't using the new testing attributes, then we can open PR's and convert the way the element is selected, it's migrating to that anyway, so I'm sure we'll only produce smiles that way ;)