[Tagging] units and notations for maxstay

[Tobias Knerr]

On 20.02.19 00:08, Warin wrote:
> 24/7 is used for opening hours - so for consistency I would tend to go
> for that.

Maxstay values are durations, opening_hours values (such as "24/7")
refer to time intervals. Those are separate concepts, so I don't think
consistency is called for.

If we want an explicit value for unlimited duration, I recommend
"unlimited". It's a simple and unambiguous solution.

Tobias