[FEA] Support map_concat function

[viadea]

I wish we can support map_concat function.
For example:

from pyspark.sql.functions import map_concat
map_concat_df1 = spark.sql("SELECT map(1, 'a', 2, 'b') as map1, map(3, 'c') as map2")
map_concat_df1.select(map_concat("map1", "map2").alias("map3")).show(truncate=False)

Not-supported messages:

! <MapConcat> map_concat(map(keys: [1,2], values: [a,b]), map(keys: [3], values: [c])) cannot run on GPU because GPU does not currently support the operator class org.apache.spark.sql.catalyst.expressions.MapConcat

[HaoYang670]

I'd like to have a try!