ECMAScript target version

[Tom Scavo]

Until recently I didn't know much about the various scripting engines
(Rhino, Nashorn, GraalVM, etc.) and how well they support the
ECMAScript standard. After doing some research on the subject, I've
concluded that the target version for sample scripts should be
ECMAScript 5.1, so I'll stick to that as best I can. This is rather
inconvenient since ECMAScript 2015 (aka ECMAScript 6) is near
universal AFAICT.

In any case, I documented suggested best coding practices in the
ScriptTypeConfiguration [1] topic. I tried to stay away from
contentious issues (involving [2], e.g.) but if you could review and
comment on what I wrote in the wiki, I'd appreciate it.

Thanks,

Tom

[1] ScriptTypeConfiguration  https://wiki.shibboleth.net/confluence/x/iQAOAg
[2] https://issues.shibboleth.net/jira/browse/JPAR-121