Add LogEntry to the views of main and views of survey

[tlrh314]

The 'History' button on an instance in the Django Admin shows a list of changes. The admin interface already keeps track of the history, but we can add a LogEntry to the survey and main views to keep a history of mutations done by users, e.g. when filling in the survey or updating their contact information at the alumnus website under account.

[tlrh314]

I have added LogEntry for the main views. The survey views should still be updated. See aaa2108.