Use ENV for redis in db-setup and fix defaults (#5951)
Use ENV for redis in db-setup and fix defaults (#5951)

* Use ENV for redis in db-setup and fix defaults

* Add default value for `DATABASE_HOST`
* Use ENV for `wait-for-it` redis and redis-slave

Signed-off-by: Adrian Nöthlich <46f1a0bd5592a2f9244ca321b129902a06b53e03@promasu.tech>

* Match default value for DATABASE_HOST
FinnStutzenstein/OpenSlides,CatoTH/OpenSlides,FinnStutzenstein/OpenSlides,CatoTH/OpenSlides,FinnStutzenstein/OpenSlides,CatoTH/OpenSlides,FinnStutzenstein/OpenSlides,CatoTH/OpenSlides