Make map default location a configurable option

Summary:
- Make map default location a configurable option
- Make it optional to fit map bounds to data on first load
- Expose map object for easier debugging

Fixes T311

Test Plan:
- In application/config/map.php : Configure a default location and zoom, disable fitDataOnMap
- Load the homepage, see the location and zoom take effect
- Delete default_view option in map.php - load homepage and default to Auckland
- Turn on fitDataOnMap - see that map moves once data loads

Reviewers: eyedol, dkobia, shadowhand

Reviewed By: dkobia, shadowhand

Maniphest Tasks: T311

Differential Revision: https://phabricator.ushahidi.com/D151