15822 state themes

This is preparation for sub-themes in aGov.

This should be functionally identical to what is there currently, with the following changes:

   * SMACCS-like structure for agov_base SCSS
   * Coding standards cleanup
   * STARTERKIT no longer clobbers global.css

Additionally, I took a moment to fix the following:

   * Blocks which didn't have full-width content now properly display full-width of their region
   * The text-resize widget can be place in any region without losing its styling
   * Fixed font body text size
   * The STARTERKIT does not override global.css, and has its own stylesheet.