Add initial Iago registration flow

This has no design consideration, but by going to <url>/initialize, an
iago user can register the app with auth, be brought to <url>finalize,
which tells them what their client ID is, and will save it for them if
the wish that to happen. It is then written to the .iago/config.json
file, though EVERYTHING in the file will be overwritten by the save
(currently).
Remove use of JavaScript redirects, add auth page layout
Consolidate config-centric files, integrate initialize flow

Config is reloaded whenever a route sets it by calling
"config = load.config()", though the config object in the load.js file
is only updated when it is saved.
Load clientId from iago config
Use google sign in for logging in