Support for more compression algorithms in addition to snappy and deflate

I was taking a quick look through [DefaultSource.scala](https://github.com/databricks/spark-avro/blob/branch-4.0/src/main/scala/com/databricks/spark/avro/DefaultSource.scala#L123-L143) and it seems there is only support for snappy and deflate. I believe Avro has support for xz and bzip2 as well.