Editor Config and Sass Guidelines

Summary:
* adds `.editorconfig`

* cleaned up spacing for easier viewing/scanning

* alphabetized sass properties

Test Plan:
* load app
* make sure nothing is broken

Reviewers: rjmackay, shadowhand

Reviewed By: shadowhand

Subscribers: sebm90, digitalafrican, eyedol, lkamau, srutto, dkobia

Differential Revision: https://phabricator.ushahidi.com/D303