(SERVER-1644) Add docs about using JAVA_ARGS_CLI from sysconfig/default
(SERVER-1644) Add docs about using JAVA_ARGS_CLI from sysconfig/default

This commit adds a note to the documentation for the gem, ruby, and irb
commands about setting the `JAVA_ARGS_CLI` option in the
sysconfig/default file for puppetserver in order to have the options
persist across future command executions.

puppetlabs/puppetserver,er0ck/puppetserver,rlinehan/puppetserver,shrug/puppet-server,rlinehan/puppet-server,puppetlabs/puppetserver,er0ck/puppetserver,rlinehan/puppetserver,camlow325/puppet-server,er0ck/puppetserver,shrug/puppet-server,er0ck/puppetserver,puppetlabs/puppetserver,camlow325/puppetserver,camlow325/puppet-server,puppetlabs/puppet-server,puppetlabs/puppet-server,camlow325/puppetserver,shrug/puppet-server,rlinehan/puppetserver,shrug/puppet-server,camlow325/puppetserver,rlinehan/puppetserver,rlinehan/puppet-server,camlow325/puppetserver,puppetlabs/puppet-server,rlinehan/puppet-server,camlow325/puppet-server,puppetlabs/puppetserver