Added screening duration to summary text

[rmbielby]

Brief overview of changes

Adding in a screening duration to the test summary stats.

Why are these changes being made?

This is being added so that it can be included as we introduce metric logging for individual tests.

Detailed description of changes

I've stored the screener trigger time (i.e. when the use triggers the screening to start) and the screening end time as a reactive values instance. So these should now be nicely retrievable however we write out to the summary lines.

I've also added the screener run duration to the summary stats.

Additional information for reviewers

Issue ticket number/s and link

Contributes to #135 (is there an appropriate keyword for that?)

[cjrace]

Approving as it's safe to go in. Though I'm not sure on the purpose of the new test files?

Also, don't think there is a keyword for 'contributes' though just referencing it will add a mention on the issue itself so there's an easy link between them automatically.

[rmbielby]

Approving as it's safe to go in. Though I'm not sure on the purpose of the new test files?

Also, don't think there is a keyword for 'contributes' though just referencing it will add a mention on the issue itself so there's an easy link between them automatically.

Those files look like they're from me demoing a potential tidy data format to someone a while back. I must have had them hanging around in my repo when I created this branch. I've removed them now to keep things tidy.