Added master_sensu role
Added required plugins from https://github.com/sensu/sensu-community-plugins
Added check_uptime.sh plugin (Nagios Plugin) from https://github.com/2600hz/chef_solo/blob/sensu/cookbooks/chef-monitor/files/default/plugins/check_uptime.sh
Added base_checks recipe, which defines the basics default checks that all servers should run
Increased interval between memory checks in the base_checks recipe