lang/bsh: switch to github

With the deprecation of Google Code and Apache Extras, the code has moved to
github.

• use Github
• use a newer snapshot that sets the target to Java 1.5 (should be more compatible with newer Java). Bump port revision accordingly
• add the "Beanshell" name to COMMENT, since PORTNAME is not clear
• pass maintainership to submitter

PR: 203354
Submitted by: pfg