Exposing Signal CLI as HTTP Server (#1078)

* Add initial proof of concept for http server

* Add support for registration commands

* Add support  for MultiLocalCommands

* Improve handling of HTTP responses

Makes it so that responses area all uniformly JSON and wrapped
into the proper response envelope.

* Add caching for workflows

* Run http server with daemon command

This fits the existing command line API better

* Wrap the existing JSON RPC handler in HTTP Service

This is a redesign of earlier attempts to make an HTTP service. Fixing
that service turned out that it would have to be a copy of the
SignalJsonRpcDispatcherHandler. So instead of copy pasting all the
code the existing service is simply being wrapped.

* Switch http server to use command handler

* Clean up and simplification

* Pass full InetSocketAddress

* Minor fixes and improvements

Based on code review.

Co-authored-by: cedb <cedb@keylimebox.org>