The availability info text can be either a one line short text such as
"Hidden from students" but it can also be a long HTML formatted text
with the list of all restricted access conditions. For the latter, using
bootstrap labels was not appropriate.
This extends the template context data with some boolean flags that
allow to better distinguish the source and meaning of the availability
information and display it accordingly.
Credit goes to Marina Glancy for the solution idea.
Ryan Wyllie