Catch missing GITHUB_TOKEN sooner

The deploy error message for missing `GITHUB_TOKEN` is a bit confusing.

This will occur on forks when they forget to set `GITHUB_TOKEN`.

Also it is wasteful to do a full master build and it fail on deploy because of missing GITHUB_TOKEN.

Start by locating the deployment and master-build configuration that reads GITHUB_TOKEN. Trace when the token is checked relative to the build, then verify that a fork with no token reports the missing configuration before running the full build.

Written by the indexing model from the issue text.