* gnu/services/guix.scm (guix-build-coordinator-agent-dynamic-auth-with-file,
guix-build-coordinator-agent-dynamic-auth-with-filen?,
guix-build-coordinator-agent-dynamic-auth-with-file-agent-name,
guix-build-coordinator-agent-dynamic-auth-with-file-token-file): New procedures.
(guix-build-coordinator-agent-shepherd-services): Handle new dynamic auth with
file record.
* doc/guix.texi (Guix Build Coordinator): Document the new dynamic auth with
file record.