Add disclosure withdrawal feature

[ryanprince]

Lobbyists need to be able to withdraw their disclosures. This feature will give lobbyists (and admin) the ability to do that by deleting a disclosure record from the system.

Description

Expected Behavior

When a disclosure is open for editing, there should be a "Withdraw Disclosure" button in a plain Bulma style, out of the way, centered at the bottom of the page. When a user clicks it, a modal should appear with the text "Withdrawing a disclosure will delete it from the system. Are you sure you want to proceed?" The modal should have a button that says "Yes, delete this disclosure." in Bulma's danger style, and a second that says "No, cancel this action." in Bulma's plain button style.

When the user finally uses the "Yes, delete this disclosure." button, a request will be sent to the server, and when the server returns that the delete was successful, the user should see a success message in the modal, and then be redirected to their dashboard.

Possible Solution

You'll need to create a delete_disclosure route in the file routes/principalDisclosure.js. It should use the requireConcernedUserOrAdmin middleware, just like the modify_disclosure route.