rapidftr/tracker#57 view all enquiries

This fix adds;
1. a view to display all the enquiries in a paginated manager
2. generalizes the styling of the children listing page to make it work for the enquiries listing page as well.
3. generailizes the searchable class to work with enquiries as well rather than children alone.
4. adds support for index enquiries when they are saved an as part of the rake task.
5. adds an EnquirySearch model to support searching and pagination of enquiries