Create new exercise for testing by clicking a button

[drieJAC]

Background

On DEVELOP only...
Be good if the exercise templates were generated from code (perhaps using a mocking library) so that dates, for example, could always be relevant (e.g. Closed for applications yesterday; Shortlisting outcome in one month; Selection Days in two month’s time). Text content could be random latin / lorem ipsum (or https://cupcakeipsum.com/) so long as we get the length roughly correct. Assigned commissioner and exercise contacts should be from our test/dummy users (e.g. seniorleader@, jacstaff@)