Remove ugly hack to generate and use an insecure certificate on the fly
in the HttpCloser's https tests and replace it with the already existing
properly generated test certificate. Removes the dependency on node-forge.
When closing down the HTTP and HTTPS servers existing connections are
not closed by Node.js, and may live on forever if they are actively in
use. A common case where this happens is if Prometheus is set up with a
short interval for collections.
To close down the active connections they need to be tracked and closed
when the server is closed, add the HttpCloser class which encapsulates
the tracking and closure process behind a simple interface and use this
to close down the HTTP and HTTPS server on the master.
Hornwitser