(PUP-3250) Remove face "secret_agent"

This removes the application and face called "secret_agent"
(PUP-3250) Update documentation after removal of "secret_agent"

As a consequence of remoging the face and application "secret_agent"
the yard documentation and manpages needed regeneration to get rid
of mentions of "secret_agent" as well as documentation generated for
the now removed face/application.
Merge pull request #3201 from hlindberg/PUP-3250-Remove-secret_agent

(PUP-3250) Remove secret agent