Upgrade Foundation, site builder and consolidate production assets

Summary:
Upgrade Node dependencies and site builder script.

Document site can now be built with yarn.

Remove servers log design test pages.

Reorganize hierarchy by service (servers-log for the servers log
for now).

Test Plan: yarn && yarn start

Reviewers: dereckson

Reviewed By: dereckson

Differential Revision: https://devcentral.nasqueron.org/D1906