WIP: Fastify rewrite

[jsumners]

This PR almost completely rewrites the server on top of Fastify instead of Hapi. The reasoning behind this is outlined in #5.

I am tagging all star gazers in this PR so that they will be aware of this massive change. Please click the "unsubscribe" button (or email link) if you do not wish to keep up with the conversation in this PR: @mahiso @orware @emersonpgomes @rwakida @dublx @sbechet @ryanhanwu

TODO

• [ ] Write up breaking changes
• [x] Clear up TODOs (see npm run todo [@charlesread ?])
• [x] Increase test coverage
• [x] Write documentation
• [x] Improve bundled theme (@chris-baldwin ?)
• [x] Add default error handler
• [x] Update cas-server-pg-registries (https://github.com/jscas/cas-server-pg-registries/pull/3)
• [x] Deprecate cas-server-theme
• [x] Update clearpass-plugin (https://github.com/jscas/clearpass-plugin/pull/1)
• [x] Update jscas-ad-auth (https://github.com/jscas/jscas-ad-auth/pull/1)
• [x] Deprecate all other "official" plugins
• [x] Fix login form for "no service" logins
• [x] Implement CLI support so the server can be installed globally
• [ ] Resolve #7

More to come as I remember them.

[jsumners]

Remaining TODOs are non-blocking.