Add support to startup parameters in init.d scripts

Current init.d scripts provided by wildfly don't have support to add startup parameters other than config files.

I plan to modify scripts to add a variable (JBOSS_OPTS) in wildfly.conf and let the user modifiy startup parameters.

It should be a trivial enhancement but I guess is late to 8.1.0 Final, so I point it to 9.0.0Alpha1.

This will allow to add additional parameters such as --backup and --cached-dc without touching startup script.