[Release][Docs] Publish docs to https://arrow.apache.org/java/current/ on release

[kou]

Describe the enhancement requested

ADBC uses https://arrow.apache.org/adbc/{current,${VERSION}} such as:

• https://arrow.apache.org/adbc/current/
• https://arrow.apache.org/adbc/15/

We can use the same approach.

ADBC does this in https://github.com/apache/arrow-adbc/blob/922a0f2b3f90267d2dbe7ff89a09d8dc9cf6d1a5/ci/scripts/website_build.sh#L49-L64 .