update cds.org codebase to use USWDS2.0

[jdkunesh]

Follow guide listed here: https://v2.designsystem.digital.gov/documentation/migration/ to create:

• a branch of cds.org that acts as a client for CDS1.1/USWDS2.0 theming.
• a new jekyll theme repo which incorporates the 2.0 styles and supports both zip file download of the full asset set and a CDN serving setup eventually.

[jdkunesh]

Great overview on how: https://www.youtube.com/watch?v=0Yp_tV7lf18&feature=youtu.be