Server lifecycle

[gtaban]

Determine the lifecycle of the HTTP server.

Refer to the discussions from #82 for history.

An initial idea discussed in that PR is:

• init: sets up the server only
• suspend: continues to accept work but doesn't process (socket would still be open, bound and listening, but not calling accept(). That will work until the kernel listen queue is full.)
• resume: resumes from suspend, starts the server if not already started.
• cancel: completely shutdown and destroy the server

@helje5 raised the point of:

For iOS, apps really need to close when going bg and completely reopen listen socks when going fg (unless you have special VoIP like blessing, in that mode the kernel will ensure the listen sockets stay alive - which may or may not be another thing we would want to support).