Add building=tent

[NieWnen]

What steps will reproduce the problem?

1. Create a building with "building=tent"
2. Run validator

What is the expected result?

No errors/warnings.

What happens instead?

(translated from PL)
Warning: Unknown property value: Value "tent" not found for the key "building"

Wiki: ​https://wiki.openstreetmap.org/wiki/Tag:building%3Dtent

Relative:URL: ^/trunk
Repository:UUID: 0c6e7542-c601-0410-84e7-c038aed88b3b
Last:Changed Date: 2020-09-06 16:54:59 +0200 (Sun, 06 Sep 2020)
Revision:17013
Build-Date:2020-09-07 01:30:48
URL:https://josm.openstreetmap.de/svn/trunk

Identification: JOSM/1.5 (17013 pl) Linux Ubuntu 18.04.5 LTS
Memory Usage: 966 MB / 8028 MB (703 MB allocated, but free)
Java version: 11.0.8+10-post-Ubuntu-0ubuntu118.04.1, Ubuntu, OpenJDK 64-Bit Server VM
Look and Feel: javax.swing.plaf.metal.MetalLookAndFeel
Screen: :0.0 1920x1080 (scaling 1.0x1.0), :0.1 1920x1080 (scaling 1.0x1.0)
Maximum Screen Size: 1920x1080
Best cursor sizes: 16x16 -> 16x16, 32x32 -> 32x32
Desktop environment: ubuntu:GNOME
Java package: openjdk-11-jre:amd64-11.0.8+10-0ubuntu1~18.04.1
Java ATK Wrapper package: libatk-wrapper-java:all-0.33.3-20ubuntu0.1
fonts-noto: fonts-noto:-
Program arguments: []
Dataset consistency test: No problems found

Plugins:
+ measurement (35405)

Tagging presets:
+ /mnt/UserData/Documents/OSM/presets/Przejscapresets.xml

Map paint styles:
+ https://josm.openstreetmap.de/josmfile?page=Styles/iD&zip=1

Last errors/warnings:
- 00005,519 W: Nie można zlokalizować pliku ''.

[skyper]

Is tent a building?
Often it is not permanent and should not be added to the database.

[mkoniecz]

Some tents are permanent or long-term.

I would not add tent as building value to presets, but I would remove Unknown property value: Value "tent" not found for the key "building" warning as this can be valid data.

[Klumbumbus]

Yes, there are a lot tents which are permanent. building=tent is fine for that.

[Klumbumbus]

In 17176/josm:

fix #19787 - Add building=tent

[Don-vip]

Milestone renamed