Style changes for volunteer opportunities edit page

- add the map to the page
- adjust fields on the edit form to be full width
- lined up the edit form with the map
- improved the styling of the error message on the page
- merge with pr 94
- staged [here](https://arcane-dusk-7252.herokuapp.com)

https://www.pivotaltracker.com/s/projects/742821/stories/79723650