[Tagging] Mixed paid, free and forbidden parking

[OSMDoudou]

> It is pay and display, so coins or you can use some sort of complicated mobile payment system.

See payment methods: https://wiki.openstreetmap.org/wiki/Key:payment#Keys

> A fee is payable between 08:00 and 18:00 Monday to Saturday, it is free on Sunday and bank holidays.

fee=Mo-Sa 08:00-18:00

Though the opening_hours tag caters for school holidays and public holidays, it doesn't support custom calendars. A separate note would be needed.

> during the paid period you can park for free for up to 15 minutes

I would put maxstay=15 minutes, but I'm not sure if it's an absolute maximum or if it can reflect the free stay: https://wiki.openstreetmap.org/wiki/Key:maxstay