Support Hive MAP columns

I get this error when using HiveSink to write to a Hive table with a `MAP` column.

```
java.lang.RuntimeException: Unsupported hive type [map]
at scala.sys.package$.error(package.scala:27)
at io.eels.component.hive.HiveSchemaFns$.fromHiveType(HiveSchemaFns.scala:56)
at io.eels.component.hive.HiveSchemaFns$.fromHive(HiveSchemaFns.scala:25)
at io.eels.component.hive.HiveSchemaFns$.fromHiveField(HiveSchemaFns.scala:22)
at io.eels.component.hive.HiveOps$$anonfun$3.apply(HiveOps.scala:144)
at io.eels.component.hive.HiveOps$$anonfun$3.apply(HiveOps.scala:144)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
at scala.collection.TraversableLike$$anonfun$map$1.apply(TraversableLike.scala:234)
at scala.collection.Iterator$class.foreach(Iterator.scala:891)
at scala.collection.AbstractIterator.foreach(Iterator.scala:1334)
at scala.collection.IterableLike$class.foreach(IterableLike.scala:72)
at scala.collection.AbstractIterable.foreach(Iterable.scala:54)
at scala.collection.TraversableLike$class.map(TraversableLike.scala:234)
at scala.collection.AbstractTraversable.map(Traversable.scala:104)
at io.eels.component.hive.HiveOps.schema(HiveOps.scala:144)
at io.eels.component.hive.HiveSink.open(HiveSink.scala:124)
at io.eels.component.hive.HiveSink$$anonfun$open$1.apply(HiveSink.scala:88)
at io.eels.component.hive.HiveSink$$anonfun$open$1.apply(HiveSink.scala:88)
at scala.collection.generic.GenTraversableFactory.tabulate(GenTraversableFactory.scala:148)
at io.eels.component.hive.HiveSink.open(HiveSink.scala:88)
at io.eels.datastream.SinkAction.execute(SinkAction.scala:46)
at io.eels.datastream.DataStream$class.to(DataStream.scala:727)
at io.eels.datastream.DataStream$$anon$50.to(DataStream.scala:772)
at io.eels.datastream.DataStream$class.to(DataStream.scala:726)
at io.eels.datastream.DataStream$$anon$50.to(DataStream.scala:772)
...
```

The error originates in HiveSchemaFns.scala at line 56, where the fromHiveType function does not handle the MAP type. Examine the Hive type system mapping in that file and the surrounding schema conversion logic. Look for existing support for other complex types like ARRAY or STRUCT to understand the pattern. Adding MAP support will likely involve updating the type matching and creating an appropriate EEL schema field.

Vom Indexierungsmodell aus dem Issue-Text verfasst.