Checklist

It would be easier to keep in single place things which we have to do
every time in specific states of the project as checklist which you can
easily review to not forget anything.

I moved some rules from our guidelines based on project states (initial,
moving to production) and added some more (e.g. binstubs flag).

Feel free to add sections or discuss adding new things there.

Should be interesting for... every participant I think, so ping: @szajbus @Ostrzy @porada @chytreg @bartoszpietrzak @sheerun @szymo @teamon @venticco @maciejswiderek