Don't gitignore application/config/ only the subdirs. Add default configs.

Summary:
Since we have environment configs, the gitignore for application/config/*.php makes less sense.
We want to include default config, but exclude dev configs.

Thoughts?

Test Plan: None.

Reviewers: eyedol, shadowhand

Reviewed By: shadowhand

Differential Revision: https://phabricator.ushahidi.com/D146