Food-Crawler crashes on unknown labels

[JonasWanke]

Describe the bug

Starting crawler HPI-MobileDev-Crawler[Food]/1.0.0 - mensaGriebnitzsee
Using User-Agent="HPI-MobileDev-Crawler[Food]/1.0.0 klaxon/5.0.11 Kotlin-runtime/1.3.50"
Date 2020-01-30: Exception in thread "main" java.lang.IllegalStateException: Unknown label "Regional"
        at de.hpi.cloud.food.crawler.MensaMeal.<init>(OpenMensaCrawler.kt:106)
        at de.hpi.cloud.food.crawler.MensaMeal.<init>(OpenMensaCrawler.kt:78)
        at de.hpi.cloud.food.crawler.OpenMensaCrawler.queryMeals(OpenMensaCrawler.kt:55)
        at de.hpi.cloud.food.crawler.MainKt$main$1.invoke(Main.kt:51)
        at de.hpi.cloud.food.crawler.MainKt$main$1.invoke(Main.kt)
        at de.hpi.cloud.common.utils.couchbase.CouchbaseClusterKt.withBucket(CouchbaseCluster.kt:35)
        at de.hpi.cloud.common.utils.couchbase.CouchbaseClusterKt.withBucket$default(CouchbaseCluster.kt:32)
        at de.hpi.cloud.food.crawler.MainKt.main(Main.kt:35)

Desired behavior: Only log a warning instead of crashing