Improve readability of examples

[sbastrakov]

As we discussed today, triggered by how the hello world example looks in new readthedocs #1093 , there are a couple of things we can do to improve readability and user-friendliness of the examples without changing their essence:

• make work div selection portable Use getValidWorkDiv() in examples instead of manually setting it #1100
• remove some of the lengthy comments of what is a queue, etc., as this belongs more to readthedocs
• gradually decouple the examples from the CI, so that ideally there is no guards or other mentions in the example bodies, and the necessary logic moved to the CI side. This may be not that easy to do, will need to investigate.