Edit agreement: improve the "unsaved changes" confirmation modal

When the user is editing an agreement, or creating a new one, and tries to exit the page without saving, if there are changes which have not been saved a modal is displayed. The following changes need to be made to this modal:

1. Change the title from "Are you sure?" to: “Close page”
2. Change the content to: “There are unsaved changes. If you would like to save your changes select Keep editing.
3. Move the button “Close without saving” to the left at the bottom (leave the "Keep editing" button where it is).

All changes are shown in the attached mockup.