Allow custom JVM options for ssoadm

[karelmaxa]

Adding of custom JVM options for ssoadm is not straightforward at the moment. User has to manually edit executable file (e.g. https://github.com/WrenSecurity/wrenam/blob/main/openam-federation/OpenFM/src/main/scripts/bin/ssoadm.bat#L46).

It would be nice to allow specifying of ssoadm JVM options using environment variables or setenv.bat|sh concept (Apache Tomcat). Any of these options would be better than manually editing the executable file.