Adds initial descriptions

Fixes #36
Adds categories and keywords descriptions

Adds descriptions to categories and keywords
Adds additional form descriptions

Fixes #37 - Adds descriptions for remaining data points in the location
editing form.
Updates colors and text

- Updates color scheme to use colors from SMC color palette.
- Updates text on description.
Merge pull request #43 from codeforamerica/37-form-input-descriptions

37 form input descriptions