Add readme_cyclic_store.md

[RobTillaart]

@Titantompa Please add a short separate document to describe the usage of the cyclic store

• short description (added value)
• interface - which calls, what do they do
• limitations?
• other notes

[Titantompa]

I tried to link the pull request to this issue, but it didn't fully link it by simply mentioning it in the pull request description. So I think you need to close the issue manually or assign me to it?

Maybe I should have paid closer attention to the docs, maybe it works fine if I'd written "closes #10"?

[RobTillaart]

if you start a commit message with "fix #11" it will automatically close things