Add PingView

[helrond]

Is your feature request related to a problem? Please describe.

Our microservice apps use the health_check library but it is incompatible with Django 4 and does not seem to be very actively maintained. We also use a very small part of the library, which can easily be reproduced in a view.

Describe the solution you'd like

Add a PingView which basically just checks to make sure the app is available.

Describe alternatives you've considered

At some point we may want this to be a more robust check, but so far we've been fine with just a simple ping.