Add 'emergency=defibrillator' to 'Is this still here?' quest

[ERYpTION]

As far as I can tell defibrillators are not included in the quest type 'Is this still here?'. I would suggest a resurvey interval of 6 months.

[FloEdelmann]

It is asked for outdoor defibrillators:

StreetComplete/app/src/main/java/de/westnordost/streetcomplete/quests/existence/CheckExistence.kt

Line 45 in a2d9b8c

or (emergency=defibrillator and indoor=no)

See #2744 (comment).