added raw params opt to ansible command and bash history key mapping
added nginx as reverse proxy with SSL support

* install nginx with SSL support from source
* SSL related setup taken from ansible-playbook-redmine
* HTTPS only, redirect from HTTP can be configured
* SSL cert is generated (self-signed) if not given
* mediatum backend and nginx form a supervisor process group
* some task refactoring
    * split off root tasks
    * run more tasks as sudo mediatum_admin_user

* Vagrant: 8081 port from host forwarded to https_port, changed hostname