Implement "Closed" status

[tswfi]

To keep some history of closed hacklabs implement new "closed" status for hacklab information

Currently accepted states are active, building, idea, restructuring (see here: https://github.com/hacklab-fi/hacklab-website/blob/master/_includes/cities.html#L4). At least one more status closed is needed. (see pr: #54 )

[janilahti]

Should closed be shown on the lab list or is the status only for storing the historical data?

[olmari]

Mostly matter of preferences... I'd say optimally there should be something shown for peoples looking around, but then again for how long etc... In the other hand if we only want to have no data anyway then we don't need "closed" status but just delete things out... So in that sense actual status should have some info shown on site...