Document image build best practices

[phillebaba]

Describe the problem to be solved

Image building behaves slightly differently from running containers. Both scenarios will pull remote images in a similar fashion. Building however will produce intermediate build layers which are cached locally on disk. On top of that alternative tools are used to be build images compared to those used to run container.

#423 raised some questions about how to get Spegel working with DIND, which brought up some differences which require configuration changes. There will likely exist similar issues with other tools.

First we will need to identify the different build scenarios that exist out there where Spegel can be used. After that we should test and document how and if Spegel can be integrated in the build process.

Proposed solution to the problem

No response