Update pl/java docs for JVM version, shared library loc, CREATE EXTEN… (#7453)
Update pl/java docs for JVM version, shared library loc, CREATE EXTEN… (#7453)

* Update pl/java docs for JVM version, shared library loc, CREATE EXTENSION command, .sql file deprecation

* Add default library location for JDK 8 and JDK 11

* format testdb; relocate uninstall topic

jmcatamney/gpdb,50wu/gpdb,greenplum-db/gpdb,xinzweb/gpdb,greenplum-db/gpdb,lisakowen/gpdb,50wu/gpdb,greenplum-db/gpdb,xinzweb/gpdb,jmcatamney/gpdb,xinzweb/gpdb,50wu/gpdb,lisakowen/gpdb,50wu/gpdb,adam8157/gpdb,adam8157/gpdb,50wu/gpdb,xinzweb/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,adam8157/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,adam8157/gpdb,lisakowen/gpdb,xinzweb/gpdb,xinzweb/gpdb,lisakowen/gpdb,jmcatamney/gpdb,lisakowen/gpdb,adam8157/gpdb,lisakowen/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,xinzweb/gpdb,ashwinstar/gpdb,lisakowen/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,adam8157/gpdb,ashwinstar/gpdb,greenplum-db/gpdb,50wu/gpdb,50wu/gpdb,ashwinstar/gpdb,adam8157/gpdb,ashwinstar/gpdb,jmcatamney/gpdb,ashwinstar/gpdb,lisakowen/gpdb,xinzweb/gpdb,adam8157/gpdb,50wu/gpdb,jmcatamney/gpdb