CB-7459 Allow auto tests to be run for specific plugin(s)

* On the "Auto Tests" page for plugins, generate a list of checkboxes to select
  each of the detected plugins.  These are initially checked based on "enabled"
  status of each plugin.

* Subsequent runs (i.e. using the existing <Again> button) will reflect any user
  changes to the selected tests

* User selections are persisted to localStorage, to remember the settings for
  subsequent runs of the app.  The enabling of test modules is encapsulated in
  the framework, so both user and console/programmatic selection are retained the
  same way via localStorage

* When the page is initially loaded, keep the existing behaviour, where all
  enabled plugin tests are automatically run

* UI enhancements to show/hide list of tests, add Select/Unselect All buttons,
  and use shorter test names