feat: Support Spark Expression Encode

[YutaLin]

Which issue does this PR close?

Closes #3183

Rationale for this change

Support expression Encode

What changes are included in this PR?

• Add StringEncode in string serde
• Update shims in spark3.4/3.5/4.0/4.1/4.2 to catch Encode

How are these changes tested?

Add encode.sql and run it in spark 3.4/3.5/4.0

[andygrove]

Thanks @YutaLin. LGTM overall. Could you address feedback, then I'll kick off CI

[YutaLin]

Hi @andygrove, thanks for the review!
I've extract encode method and add null check.

About "Spark accepts utf8 as an alias for UTF-8", spark only supports alias before 3.5, because it uses JDK Charset.forName. After 4.0, it has a whitelist check, so it doesn't support alias. I'd suggest we keep only utf-8 now, WDYT?

https://spark.apache.org/docs/4.0.0/sql-migration-guide.html#upgrading-from-spark-sql-35-to-40

Since Spark 4.0, the encode() and decode() functions support only the following charsets ‘US-ASCII’, ‘ISO-8859-1’, ‘UTF-8’, ‘UTF-16BE’, ‘UTF-16LE’, ‘UTF-16’, ‘UTF-32’. To restore the previous behavior when the function accepts charsets of the current JDK used by Spark, set spark.sql.legacy.javaCharsets to true.