This adds UI support for receiving the one-time token passed via query parameter, as in #10134
and related PRs, and exchanging it for its corresponding secret ID. When this works, it’s mostly
invisible, with a brief flash of the OTT onscreen.
The authentication failure message now suggests the -authenticate flag.
When OTT exchange fails, it shows a whole-page error.
This includes a known UX shortcoming in that the OTT will not disappear from the URL when an
identifier is specified on the command line, like nomad ui -authenticate jobname. The goal is to
address that shortcoming in a forthcoming pull request.
6d67e90763