Add custom input component support to the Web UI config in order to
provide a user friendly dropdown selector for the Mod Pack that is
configured as default on the controller and overridden instances.
The control interface is required for adding handlers for message types
a plugin defines, but the plugins were loaded before the Control
instance was created. This meant there was no sensible way for web
plugins to register handlers for their own message types.
Move the creating of the Control instance to before plugins are loaded
and set this.control for web plugins before init is called.
Move BaseControllerPlugin to controller/src/BaseControllerPlugin.ts
Move BaseInstancePlugin to host/src/BaseInstancePlugin.ts
Move BaseControlPlugin to ctl/src/BaseCtlPlugin.ts
Move BaseWebPlugin to web_ui/src/BaseWebPlugin.ts
This solves the circular package dependency problem of the base plugins
needing types that are available only in the dependencies to lib.
Cooldude2606