add driving fields to downloadable report for admins

[Zrrrpy]

Part of epic #4

What type of user is this for? [admin/supervisor/volunteer/all]
admin

Where does/should this occur?
in the report admins can download displaying all case_contact details in a .csv – accessed on this page.

Description
Add 2 columns to report downloaded from admin dashboard:
1 - column displaying miles driven
2 - column displaying whether or not reimbursement is requested

Empty fields in these columns may remain empty (no need to display "null" or "false".