net/activemq: Update 5.18.3 => 6.2.0, improve port
Release Notes:
https://issues.apache.org/jira/secure/ReleaseNote.jspa?projectId=12311210&version=12354379
https://activemq.apache.org/components/classic/download/classic-06-02-00
Improve port:
- Replace PORTVERSION with DISTVERSION.
- Set JAVA_VERSION to supported LTS versions: https://activemq.apache.org/components/classic/download/
- Parametrize activemq with PORTNAME.
- Optimize do-install: merge REINPLACE_CMD, MKDIR, split long lines.
- Improve rc script - use JAVA_HOME.
PR: 292549
Approved by: James Elstone <james@elstone.net> (maintainer, timeout 2 weeks)