We have lots of functions for converting various types of data into
strings to be displayed to the user somewhere.
This commit collects all these functions into their own module, rather
than having them cluttering up `app/__init__.py` or buried amongst
various other things that have ended up in `app/utils.py`.
The property doesn’t represent the whole client, but just one method on
it. So this commit renames the property to better describe what it is
designed to store.
We store our audit history in two ways:
1. A list of versions of a service
2. A list of events to do with API keys
In the future there could be auditing data which we want to display that
is stored in other formats (for example the event table).
This commit adds some objects which wrap around the different types of
auditing data, and expose a consistent interface to them. This
architecture will let us:
- write clean code in the presentation layer to display these events on
a page
- add more types of events in the future by subclassing the `Event` data
type, without having to rewrite anything in the presentation layer
