[Docs] Redirect https://arrow.apache.org/java/ to https://arrow.apache.org/java/current/

[kou]

Describe the enhancement requested

https://arrow.apache.org/java/current/ doesn't exist yet but it shows the documents for the latest release.

How to implement:

• ADBC uses <meta http-equiv="Refresh">: https://github.com/apache/arrow-adbc/blob/asf-site/index.html
• We can use .htaccess like arrow-go does: https://github.com/apache/arrow-go/blob/asf-site/.htaccess

[kou]

Done by #575.