Add course location and external reference to members course element email template

In the member list course element authors or coaches can send emails to the course members. In the email template the course title and link to the course is added. 

If managing multiple courses it is sometimes hard to keep track of the context where the user is in . If a course with the same name is held at different location for example, it is noch visible while editing the mail message for which location the course is. To help this situation we added the course location and the course external reference to the code that feeds the course template. 

Note that we did not change the mail template as this is a setup that only makes sense when working with locations. If you need this in your own installation, make sure to use the language adaption tool in the admin site to overwrite the standard mail template. 

variable 2: the external reference
variable 3: the course location

Package: org.olat.course.nodes.members
Key: email.body.template=<p /><p /><p>Link zum Kurs <strong>{0}</strong>:<br /><a href\='{1}'>{1}</a></p><p>Kennzeichen: {2}<br />Durchführungsort: {3}</p>