The expiry field we get from Google is not a timestamp, but a count of
seconds after which the token is invalid (hence, 'expires_in'). We
represent this as a @dr by multiplying the integer we get from Google by
~1s. (Perhaps it will wind up being easier on the Landscape side to
consume the raw integer, but we may as well start off more
type-correct.)
Also cleans up some names now that I'm less confused about how the token
API works, and makes some syntax more vertical.
The correct scope to ask for is not devstorage.editor, but
cloud-platform. This will, rather than returning a signed JWT from
Google that looks like it works but doesn't, return a JSON object
containing an access token and expiration time.
Moves =, closer to call sites so it's clearer what's coming from where.
Also uses +ot, allowing a less horrifying +sign-jwt. This also seems to
not jump back and forth between tapes and cords as much, for what that's
worth.