This commit adds a new configuration file jvm.options to centralize and
simplify management of JVM options. This separates the configuration of
the JVM from the packaging scripts (bin/elasticsearch*, bin/service.bat,
and init.d/elasticsearch) simplifying end-user operational management of
custom JVM options.
2.x has show so far that running with security manager is the way to go.
This commit make this non-optional. Users that need to pass their own rules
can still do this via the system configuration for the security manager. They
can even opt out of all security that way.