Design st2::profile::server split

This is a design document for splitting up st2::profile::server

Initial thoughts:

• To follow the pattern setup by other common/popular st2 modules, we should probably put these "services" into st2::server (st2/server) directory
• Each service would have its own class, example st2::server::actionrunner
• Configs should have their own classes, because many of the services share common configs like [db]
• Configs should live in its own directory st2::server::config (st2/server/config
• Each config section should have its own config class st2::server::config::db, st2::server::config::actionrunner, etc