Enable deleting multiple projects, style action links and buttons in List views and create different types of TempData messages

- Add selectCheckboxes.js file for selecting and deselecting all checkboxes
- Move the Action column on the beginning of the project table and add checkboxes to the first row
- Style links and submit input types and add required images
- Add POST Delete action method in Project controller for deleting multiple items
- Add MultipleButtonAttribute class for distinguishing two Delete submit inputs in the same form (Create temporary Delete GET method for deleting projects directly from the table)
- Change TempData message name to message-success
- In _Layout consider three different types of messages and apply different styles accordingly
- Add unit test for bulk deletion and update other tests to accommodate created changes