[SPARK-9929] [SQL] support metadata in withColumn

in MLlib sometimes we need to set metadata for the new column, thus we will alias the new column with metadata before call `withColumn` and in `withColumn` we alias this clolumn again. Here I overloaded `withColumn` to allow user set metadata, just like what we did  for `Column.as`.

Author: Wenchen Fan <cloud0fan@outlook.com>

Closes #8159 from cloud-fan/withColumn.