[SPARK-35247][SQL] Add mask built-in function as a data masking function

[sarutak]

What changes were proposed in this pull request?

This PR proposes to add a new built-in function mask a data masking function which Hive already supports.

Actually, Hive supports 6 data masking functions.
I'll implement all of them but I'd like to introduce the most basic one in this PR.

mask in this PR is implemented to be compatible with the Hive's implementation.
In Hive, there is a [document}(https://cwiki.apache.org/confluence/display/Hive/LanguageManual+UDF#LanguageManualUDF-DataMaskingFunctions) for data masking functions but it seems outdated so I referred to the Hive's source code.
https://github.com/apache/hive/blob/rel/release-2.3.8/ql/src/java/org/apache/hadoop/hive/ql/udf/generic/GenericUDFMask.java

Actually, Hive's data masking functions can be applied to not only characters but also numeric types and date type.
In this PR, mask supports only StringType but I'll extends it for other types. So, this new function is categolized as a new group data_masking_funcs rather than string_funcs.

Why are the changes needed?

For data masking, mask is more useful than replace or translate.

Does this PR introduce any user-facing change?

Yes. Users can use the new built-in function.

How was this patch tested?

New tests.

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/42526/

[SparkQA]

Kubernetes integration test status failure
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/42526/

[SparkQA]

Test build #138007 has finished for PR 32372 at commit f6baec9.

• This patch fails Spark unit tests.
• This patch merges cleanly.
• This patch adds the following public classes (experimental):
• case class Mask(
• class MaskTransformer()

[SparkQA]

Kubernetes integration test starting
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/42533/

[SparkQA]

Kubernetes integration test status failure
URL: https://amplab.cs.berkeley.edu/jenkins/job/SparkPullRequestBuilder-K8s/42533/

[yaooqinn]

The Hive data masking functions were removed in #21786

[SparkQA]

Test build #138014 has finished for PR 32372 at commit 09227e7.

• This patch passes all tests.
• This patch merges cleanly.
• This patch adds no public classes.

[sarutak]

The Hive data masking functions were removed in #21786

oh... I didn't notice.