* introduce start phase. setup is bloated with start functionality
* fix amp typings: server is part of start contract now
* update mock files
* root.start(): necessary to run test server
* expose setup&start server api to simplify testing
* move tests to the new API
* test servers also should call root.start()
* update docs
* update snapshots: this functionality is tested in http server
* split setup/start phases
* update docs
* expose http server if it not started
to get rid of Optional<HttpServer> type and make it Require<HttpServer>
* adopt test to exposed Http server via SetupContract
* udpate docs
* cleanup apm changees
* check legacy service setup before start
* check http server setup before start
* restrict server options mutation; unify Promise interface for setup
* introduce start pahse for plugins service for parity with client side
* Revert "introduce start pahse for plugins service for parity with client side"
This reverts commit c04fdd2e26.
39091e7037