[SPARK-3412][SQL]add missing row api

chenghao-intel assigned this to me, check PR #2284 for previous discussion

Author: Daoyuan Wang <daoyuan.wang@intel.com>

Closes #2529 from adrian-wang/rowapi and squashes the following commits:

c6594b2 [Daoyuan Wang] using boxed
7b7e6e3 [Daoyuan Wang] update pattern match
7a39456 [Daoyuan Wang] rename file and refresh getAs[T]
4c18c29 [Daoyuan Wang] remove setAs[T] and null judge
1614493 [Daoyuan Wang] add missing row api
[SPARK-3858][SQL] Pass the generator alias into logical plan node

The alias parameter is being ignored, which makes it more difficult to specify a qualifier for Generator expressions.

Author: Nathan Howell <nhowell@godaddy.com>

Closes #2721 from NathanHowell/SPARK-3858 and squashes the following commits:

8aa0f43 [Nathan Howell] [SPARK-3858][SQL] Pass the generator alias into logical plan node
[SPARK-3813][SQL] Support "case when" conditional functions in Spark SQL.

"case when" conditional function is already supported in Spark SQL but there is no support in SqlParser. So added parser support to it.

Author : ravipesala ravindra.pesalahuawei.com

Author: ravipesala <ravindra.pesala@huawei.com>

Closes #2678 from ravipesala/SPARK-3813 and squashes the following commits:

70c75a7 [ravipesala] Fixed styles
713ea84 [ravipesala] Updated as per admin comments
709684f [ravipesala] Changed parser to support case when function.