display number of potential matches on the home screen

rapidftr/tracker#69 
This fix;
1. adds an extra section on the show page of an enquiry to show the child potential matches associated with the enquiry.
2. adds a fix to formsections setup features step to stop the removal of all formsections in the system before creating the specified one.
   This fix ensures that the formsection that matches the specified name, will be the one destroyed.
3. adds an extra step to the enquiries api features to first reset the forms including the formsections. This is to ensure that the
   datastore is consistent with the expectations of the tests.
4. adds a separate page to show only enquiries with potential matches.
5. adds a link to the home page showing the number of enquiries with potential matches and links to the potential matches page.