Documentation: Document in which conditions a block is closed

[haozturk]

This is discussed at the WM training today. Alan mentioned a few conditions which is used to decide whether to close a block or not. It'd be useful to document all cases [1]

[1] https://indico.cern.ch/event/1403826/

[amaltaro]

Thank you for creating it, Hasan. If possible, for future tickets, please stick to the templates offered in the project.