[Tagging] Feature Proposal - RFC - Deprecate departures_board=realtime

[Dimitar]

> - it can be used both as a characteristic of a stop (public_transport=plateform + departures_board=realtime) and to describe the board itself, for example in a large station (tourism=information + information=board + board_type=public_transport departures_board=realtime even if this sequence is a bit long)

That also applies to passenger_information_display.

> - it allows the grouping of 3 panel shades with the same purpose in the same key

And it makes processing data a hassle. With the same success you can
have infrastructure=shelter;bench;bin instead of the respective keys.

> - semantically imprecise, I wouldn't be surprised if it was used for information panels other than real-time timetables (e.g. covid information panels or other general information in stations)

Would realtime_departure_board be a better alternative? If not do you
have better suggestions?

> - because of the choice of value=yes/no it is not possible to bring nuances other than by creating a new value2=yes/no

Can you give an example of a nuance?

>  let's be honest :) if a plateform have 3 departures_board, replacing one with a value=yes/no does not change the need for good tools to handle the ";"

Again, how many tools do that? In my honest opinion, having less such
cases is better than having more.